Selective deposition of metallic films

ABSTRACT

Metallic layers can be selectively deposited on one surface of a substrate relative to a second surface of the substrate. In some embodiments, the metallic layers are selectively deposited on a first metallic surface relative to a second surface comprising silicon. In some embodiments the reaction chamber in which the selective deposition occurs may optionally be passivated prior to carrying out the selective deposition process. In some embodiments selectivity of above about 50% or even about 90% is achieved.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. applicationSer. No. 15/177,198, filed Jun. 8, 2016, and entitled “SELECTIVEDEPOSITION OF METALLIC FILMS,” and U.S. application Ser. No. 15/177,195,filed Jun. 8, 2016, and entitled “REACTION CHAMBER PASSIVATION ANDSELECTIVE DEPOSITION OF METALLIC FILMS,” and is related to U.S.application Ser. No. 13/708,863, filed Dec. 7, 2012, and entitled“SELECTIVE FORMATION OF METALLIC FILMS ON METALLIC SURFACES” whichclaims priority to U.S. Provisional Application No. 61/569,142, filedDec. 9, 2011, the disclosures of which are hereby incorporated byreference in their entireties.

BACKGROUND Field

The present application relates generally to the field of semiconductorfabrication.

Description of the Related Art

Integrated circuits are currently manufactured by an elaborate processin which various layers of materials are sequentially constructed in apredetermined arrangement on a semiconductor substrate.

Meeting the ever increasing electromigration (EM) requirement in copperinterconnects is becoming more difficult as Moore's law progresses,resulting in smaller devices. As line dimensions shrink, critical voidsize for EM failure is also reduced, causing a sharp decrease in meantime to failure. A significant improvement in EM resistance is requiredto enable continued scaling.

The interface between the dielectric diffusion barrier and metallicmaterial has been shown to be the main path for metallic materialdiffusion and the weakest link in resisting EM failure. Theimplementation of a selective metal cap has been challenging because ofthe difficulty in achieving good selectivity on metallic surfaces versusthe dielectric surface. Methods are disclosed herein for selectivedeposition of metallic films that can be used in this context todecrease electromigration.

Selective deposition of tungsten advantageously reduces the need forcomplicated patterning steps during semiconductor device fabrication.However, gentle surface treatments, such as thermal or radicaltreatments are typically preferred to provide desired surfaceterminations for selective deposition. Such surface treatments may notadequately prepare the desired surface for selective deposition, leadingto a loss of selectivity.

SUMMARY

According to some aspects, processes for selectively depositing a filmon a first metallic surface of a substrate relative to a seconddielectric surface of the same substrate are described. In someembodiments the process may comprise performing a first metallic surfacetreatment process comprising removing a surface layer from the firstmetallic surface of the substrate such that a significant amount of newsurface groups or ligands are not provided on the second dielectricsurface by the first metallic surface treatment process; and selectivelydepositing a film on the first metallic surface of the substraterelative to the second dielectric surface of the substrate with aselectivity of greater than about 50%.

In some embodiments the first metallic surface treatment processcomprises exposing at least the first metallic surface of the substrateto a plasma generated from a gas. In some embodiments the first metallicsurface treatment process comprises exposing the first metallic surfaceof the substrate and the second dielectric surface of the substrate tothe plasma generated from the gas. In some embodiments the firstmetallic surface treatment process further comprises reducing and/orremoving a metal oxide layer present on the first metallic surface ofthe substrate. In some embodiments the removed surface layer comprisesan organic material. In some embodiments the removed surface layercomprises a passivation layer. In some embodiments the removed surfacelayer comprises benzotriazole (BTA). In some embodiments the gascomprises carbolic acid. In some embodiments the gas comprises formicacid (HCOOH) and H₂. In some embodiments the gas comprises HCOOH, NH₃,and H₂. In some embodiments the gas is provided by a carrier gascomprising a noble gas. In some embodiments a temperature of thesubstrate during the first metallic surface treatment process is about300° C. In some embodiments the first metallic surface treatment processcomprises exposing at least the first metallic surface of the substrateto the plasma for from about 1 second to about 10 minutes. In someembodiments the plasma is generated by supplying RF power of from about10 W to about 3000 W to the gas. In some embodiments the frequency ofthe RF power is from about 1 MHz to about 10 GHz. In some embodimentsthe pressure of the gas from which the plasma is generated is from about1 Pa to about 5000 Pa. In some embodiments the selectively depositedfilm comprises tungsten. In some embodiments the first metallic surfacecomprises copper or cobalt. In some embodiments the second dielectricsurface comprises silicon.

In some aspects processes for selectively depositing a film on a firstmetallic surface of a substrate relative to a second dielectric surfaceof the same substrate are described. In some embodiments the process maycomprise performing a first metallic surface treatment processcomprising removing a surface layer from the first metallic surface ofthe substrate by exposing at least the first metallic surface of thesubstrate to a plasma generated from a gas comprising HCOOH; andselectively depositing a film on the first metallic surface of thesubstrate relative to the second dielectric surface of the substratewith a selectivity of greater than about 50%.

In some aspects processes are presented herein for selectivelydepositing a film on a substrate comprising a first metallic surface anda second surface comprising silicon. In some embodiments the processesmay comprise passivating a reaction chamber in which a selectivedeposition process is to be performed, subjecting the substrate to afirst surface treatment process comprising exposing the substrate to aplasma, subsequent to the first surface treatment process, performingone or more selective deposition cycles in the reaction chamber, eachcycle comprising contacting the substrate with a first precursorcomprising silicon or boron to selectively form a layer of firstmaterial comprising Si or B on the first metallic surface relative tothe second surface comprising silicon, and converting the first materialon the first metallic surface to a second metallic material by exposingthe first material to a second precursor comprising metal. In someembodiments the second metallic material is deposited on the firstmetallic surface of the substrate relative to the second surfacecomprising silicon with a selectivity of greater than about 50%.

In some embodiments the first metallic surface comprises copper. In someembodiments the first metallic surface comprises cobalt. In someembodiments the second surface comprising silicon comprises SiO₂. Insome embodiments the second metallic material comprises tungsten. Insome embodiments passivating the reaction chamber comprises depositing apassivation layer on surfaces in the reaction chamber which may beexposed to the first or second precursor during one or more of theselective deposition cycles. In some embodiments the passivation layeris formed by a vapor deposition process. In some embodiments thepassivation layer is formed by a plasma enhanced chemical vapordeposition (PECVD) process. In some embodiments the passivation layer isformed by a plasma enhanced atomic layer deposition (PEALD) process. Insome embodiments the passivation layer is formed by conducting a firstvapor phase silicon precursor and a second vapor phase nitrogenprecursor into the reaction chamber and wherein a plasma is present inthe reaction chamber. In some embodiments the passivation layer isformed by alternately and sequentially exposing the reaction chamber toa first precursor comprising disilane and a second precursor comprisingatomic nitrogen, nitrogen radicals, or nitrogen plasma and atomichydrogen, hydrogen radicals or hydrogen plasma.

In some embodiments the passivation layer comprises SiN. In someembodiments the plasma is generated from ethanol. In some embodimentsthe plasma is generated from NH₃ and H₂. In some embodiments the firstprecursor comprises a silane. In some embodiments the first precursorcomprises disilane. In some embodiments the second precursor comprises ametal halide. In some embodiments the second precursor comprises WF6. Insome embodiments the process further comprises subjecting the substrateto a second surface treatment process prior to subjecting the substrateto a first surface treatment process. In some embodiments the secondsurface treatment process comprises exposing the substrate to atreatment reactant, wherein the treatment reactant passivates the secondsurface. In some embodiments the second metallic material is depositedon the first metallic surface of the substrate relative to the secondsurface comprising silicon with a selectivity of greater than about 90%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart generally illustrating a process for selectivelydepositing a metal film on a first metallic surface of a substraterelative to a second silicon containing surface.

FIG. 2A is a schematic diagram of an exemplary substrate comprising afirst metallic surface having a metal oxide layer and a passivationlayer disposed thereon, and a second dielectric surface.

FIG. 2B is a schematic diagram of the exemplary substrate of FIG. 5Aafter being subjected to a surface treatment process and a process forselectively depositing a metal film on the first metallic surface asdescribed herein and according to some embodiments.

FIG. 3 is a flow chart illustrating a process for selectively depositinga metal film on a first metallic surface of a substrate relative to asecond silicon containing surface according to certain embodiments.

FIG. 4 is a flow chart illustrating a process for selectively depositinga metal film on a first metallic surface of a substrate relative to asecond silicon containing surface according to certain otherembodiments.

FIG. 5 is a flow chart generally illustrating a process for passivatinga reaction chamber prior to performing a selective deposition processtherein.

FIG. 6A is a scanning electron micrograph showing blanket deposition ofW on a substrate comprising a first Cu surface and a second low-ksurface that was subjected to a surface treatment process comprisingexposing the substrate to plasma generated from H₂.

FIG. 6B is a scanning electron micrograph showing blanket deposition ofW on a substrate comprising a first Cu surface and a second low-ksurface that was subjected to a surface treatment process comprisingexposing the substrate to plasma generated from H₂ and N₂.

FIG. 6C is a scanning electron micrograph showing blanket deposition ofW on a substrate comprising a first Cu surface and a second low-ksurface that was subjected to a surface treatment process comprisingexposing the substrate to plasma generated from NH₃.

FIG. 6D is a scanning electron micrograph showing blanket deposition ofW on a substrate comprising a first Cu surface and a second low-ksurface that was subjected to a surface treatment process comprisingexposing the substrate to plasma generated from NH₃ and H₂.

FIG. 7 is a scanning electron micrograph showing selective deposition ofW on a first Cu surface of a substrate relative to a second low-ksurface of the substrate that was subjected to a surface treatmentprocess comprising exposing the substrate to plasma generated fromHCOOH, NH₃, and H₂.

DETAILED DESCRIPTION

In some embodiments, methods are disclosed for selective deposition ofmetallic films on metal or metallic materials while avoiding depositionon silicon containing materials, such as silicon dioxide. For example, ametallic film may be deposited on copper for end of the line substrateprocessing. In some embodiments, metallic films are deposited on anintegrated circuit workpiece comprising copper lines in siliconcontaining material.

In some such applications, the selective deposition methods disclosedherein can be used to deposit material onto copper thereby decreasingelectromigration of the copper. In some embodiments, the selectivedeposition is on the copper metal layers and not on silicon containingmaterials on the substrate. Deposition on the silicon containingmaterials in these applications is undesirable because it can decreasethe effective dielectric value.

In some embodiments, the process flows described herein are used toselectively deposit metal on micrometer-scale (or smaller) featuresduring integrated circuit fabrication. In some embodiments feature sizemay be less than 100 micrometers, less than 1 micrometer or less than200 nm. In the case of selective deposition of W on Cu for interconnectapplications, in some embodiments the feature size/line widths may beless than 1 micrometer, less than 200 nm, less than 100 nm, or even lessthan 50 nm. Of course the skilled artisan will recognize that selectivedeposition on larger features and in other contexts is possible usingthe disclosed methods.

In some embodiments, the selective deposition can avoid additionalprocessing steps, thereby saving time and decreasing the costsassociated with processing the substrates. For example, lithography willbe very expensive in the future for small dimensions. With 8 or morelayers of Cu metallization in the chips, the time and cost savingsachievable using selective deposition are magnified because time issaved for each area of copper metallization during substrate processing.Also, the methods disclosed herein can obviate the need for diffusionbarriers and other processing steps.

In some embodiments processes are disclosed for removing a surface layeror layers from a first metallic surface of a substrate. In someembodiments the surface layer removal process may remove a surface layerpresent on the first metallic surface of the substrate. For example, thesurface layer removal process may remove a surface layer present on thefirst surface of the substrate in order to enable or enhance selectivedeposition thereon. In some embodiments the surface layer that isremoved may comprise a layer of organic material. That is, in someembodiments a surface layer removal process may remove any organicmaterial present on the first metallic surface. For example a surfacelayer removal process may remove an organic passivation layer present onthe first metallic surface. For example, the surface layer removalprocess may remove a benzotriazole (BTA) passivation layer from a coppersurface of an integrated circuit workpiece. In some embodiments thesurface layer removal process may remove any organic and/or hydrocarbonlayer that may be present on the first metallic surface.

In some embodiments the surface layer removal process may reduce asurface layer or portion of a surface layer present on the firstmetallic surface of the substrate. In some embodiments the surface layerremoval process may reduce and/or remove any oxide surface layer presenton the first metallic surface. In some embodiments surface layer removalprocess may reduce and/or remove any native oxide layer that may bepresent on the first metallic surface. In some embodiments the surfacelayer removal process may provide active sites on the first metallicsurface, for example by reducing and/or removing a surface layer orportion of a surface layer present on the first metallic surface. Insome embodiments an oxide layer may be partially removed and theremaining material comprising the oxide layer may be reduced by thesurface layer removal process. That is, in some embodiments a portion ofthe oxide layer may be removed by the surface layer removal process,while any remaining oxide layer may be reduced by the surface layerremoval process. In some embodiments substantially all of an oxidesurface layer may be removed by the surface layer removal process. Insome embodiments substantially all of an oxide surface layer may bereduced by the surface layer removal process.

As used herein, the term reduce may refer to the chemical conversion ofan oxide material to its non-oxide form. That is, when a metal oxidematerial is reduced, it is chemically converted to the metal of themetal oxide. For example a copper oxide layer may be present on a firstmetallic surface comprising copper and surface layer removal may reducethe copper oxide layer such that it is converted to metallic copper. Insome embodiments the surface layer may comprise both an organic surfacelayer and an oxide layer underlying the organic surface layer. In someembodiments where the first metallic surface may comprise a surfacelayer comprising an organic surface layer and an oxide layer underlyingthe organic surface layer, the surface layer removal process may removethe organic surface layer and may also reduce and/or remove the oxidelayer, thereby providing a clean first metallic surface.

In some embodiments, the first metallic surface of the substrate issubjected to a surface layer removal process comprising exposing thesubstrate to a plasma generated from a gas. In some embodiments thesurface layer removal process may comprise exposing at least the firstsurface to the plasma. In some embodiments the surface layer removal maycomprise exposing the first surface and a second surface of thesubstrate to the plasma. Such a surface layer removal process may, forexample, remove a passivation layer present on a first metallic surface,such as a Cu surface. Such a surface layer removal process may also, forexample, reduce and/or remove an oxide layer from the first metallicsurface, such as reducing and/or removing a copper oxide layer from a Cusurface

In some embodiments a plasma generated from a gas comprising one or moreorganic compounds can be used in the surface layer removal process. Insome embodiments a plasma generated from a gas comprising a compound, asdescribed herein, can be used in the surface layer removal process. Insome embodiments a plasma generated from a gas comprising formic acid(HCOOH) can be used in surface layer removal process. In someembodiments a plasma generated from a gas comprising carbolic acid canbe used in the surface layer removal process. In some embodiments aplasma generated from a gas comprising HCOOH and NH₃ can be used in thesurface layer removal process. In some embodiments a plasma generatedfrom a gas comprising HCOOH and H₂ can be used in the surface layerremoval process.

In some embodiments a plasma generated from a gas comprising HCOOH, NH₃,and H₂ can be used in the surface layer removal process. In someembodiments a plasma may be generated from a gas comprising HCOOH, NH₃,and H₂ where the ratio of HCOOH to NH₃ to H₂ is from about 1:1:5 toabout 1:1:20, or from about 1:1:9 to about 1:1:19. In some embodimentsthe ratio of HCOOH to NH₃ to H₂ is about 1:1:19. Advantageously,exposing a first metallic surface of a substrate to a plasma generatedfrom a gas comprising HCOOH, NH₃, and H₂ may remove any passivationmaterial present on the first metallic surface and may also reduceand/or remove any native oxide material that is present on the firstmetallic surface. Further, a surface layer removal process comprisingexposing the substrate to a plasma generated from a gas comprisingHCOOH, NH₃, and H₂ may not provide any additional or new surface groupsor ligands to a second surface, such as a second dielectric surface ofthe substrate. In this way, such as a surface layer removal process maybe used to prepare a first metallic surface of a substrate, such as anintegrated circuit workpiece, for deposition thereon, without the needto provide a masking or protected layer over other surfaces of thesubstrate, or without the need for further treating a second surface ofthe substrate, for example to passivate the second surface against thinfilm deposition. Such a surface layer removal process may thereforesimplify and/or reduce the number of processing steps required inselective deposition and/or integrated circuit manufacturing processes.

FIG. 1 is a flow chart generally illustrating a process 10 forselectively depositing a metal film on a first metallic surface of asubstrate relative to a second silicon containing surface. In someembodiments the process may comprise an optional reaction chamberpassivation step 11 prior to a selective deposition step 14 in order toenable selective deposition, improve selectivity, and/or increase thenumber of consecutive cycles before selectivity is lost during aselective deposition process. In some embodiments the reaction chamberpassivation step 11 may increase the number of consecutive cycles inwhich a desired level of selectivity is achieved. The optional reactionchamber passivation step 11 may include providing a passivation materialor passivation layer on chamber surfaces and other locations which maybe exposed to a precursor or reactant during the selective depositionstep 14. The reaction chamber passivation step 11 may limit or preventdeposition of metallic material on chamber surfaces during a subsequentselective deposition step 14, thereby reducing or eliminating the amountof reactive byproducts generated by the selective deposition step 14. Insome embodiments the reaction chamber passivation step 11 may reducecontamination of the substrate during the selective deposition step 14which in turn may enable selective deposition or increase selectivity.

In some embodiments the passivation layer may comprise, for example,SiN. In some embodiments the passivation layer may comprise a metaloxide and may be formed by, for example, oxidizing a metallic materialthat is present on chamber surfaces. In some embodiments the passivationlayer may not be pure metal or pure silicon.

Selective deposition using the methods described herein does not requiretreatment of the silicon containing layer to block deposition thereon.As a result, in some embodiments the second surface comprising silicondoes not comprise a passivation or blocking layer, such as aself-assembled monolayer (SAM), which would prevent the actual topsurface of the second dielectric surface from being exposed to thechemicals of the deposition processes described herein. Thus, in someembodiments the film is deposited selectively on the first metal surfaceon a substrate which has not received treatment designed to preventdeposition of the film on the second silicon containing surface, such asa blocking or passivation treatment. That is, in some embodimentsselective deposition can be obtained even though deposition is notblocked on the second surface comprising silicon by a blocking orpassivation layer. Instead, the deposition conditions are selected suchthat the selective deposition process will occur without the need forpretreatment of the second surface comprising silicon prior todeposition.

In some embodiments the second silicon containing layer may be exposedto a treatment designed to treat the first surface. For example, in someembodiments it is desirable to passivate the first metal surface and thesecond surface comprising silicon may be exposed to the same passivationtreatment as the first metal surface. For example, in the case of Cuboth the first Cu surface and the second surface comprising silicon maybe exposed to benzotriazole (BTA) or another passivating chemical.However, no specific further treatments or exposures (besides what itmay receive during transportation of the sample) are done for the secondsurface comprising silicon before a first surface treatment step toremove the passivation layer from the metal surface. In particular notreatment designed to block deposition of the film on the second surfacecomprising silicon need be carried out.

In some embodiments at the time of selective deposition of the film, thesecond dielectric surface comprises only surface groups that arenaturally occurring in the low-k material, and does not comprise asignificant amount of functional groups or ligands that would notnaturally be present in the low-k material itself. In some embodimentsno active treatment of the second dielectric surface is carried outafter first surface treatment that would add surface groups to thesecond dielectric surface. In some embodiments the second dielectricsurface comprises only surface groups that are naturally occurring inlow-k materials, including those that could be formed during fortransportation of the substrate in air, for example.

However, in some embodiments the second silicon containing surface mayoptionally be treated at step 12. In some embodiments, a siliconcontaining surface can be treated at step 12 to enhance the selectivityof the deposition process by decreasing the amount of material depositedon the silicon containing surface, for example by passivating thesilicon containing surface. In some embodiments the treatment step 12 isintended to restore the silicon containing layer and not to blockdeposition on the silicon containing layer. In some embodiments thesecond silicon containing surface treatment at step 12 may comprisecontacting the second surface with treatment chemical, for example thesecond surface comprising silicon may be contacted with a treatmentchemical comprising trimethyl(dimethylamino)silane. In some embodimentsthe substrate may be outgassed at the beginning of or prior to step 12in order to remove, for example, any moisture from the substrate surfaceor inside the silicon containing material.

In some embodiments the substrate surface is cleaned or treated at step13 prior to beginning the selective deposition step 14. In someembodiments the first surface treatment step 13 may comprise exposingthe substrate to a plasma, for example a plasma generated from a gascomprising HCOOH, NH₃, and H₂. In some embodiments the first surfacetreatment step 13 may comprise a process for removing a surface layerfrom the first metallic surface as described herein. In some embodimentsthe first surface treatment step 13 may comprise exposing the substrateto a vapor phase treatment chemical, for example formic acid. In someembodiments the first surface treatment step 13 may reduce and/or removea surface layer form the first metallic surface. In some embodiments thefirst surface treatment step 13 may reduce and/or remove any nativeoxide that may be present on the first metallic surface. Although insome embodiments a native oxide may still be present on the firstsurface after the first surface treatment step 13. In some embodimentsthe first surface treatment step 13 may remove any surface layer, forexample an organic or hydrocarbon surface layer that may be present onthe first metallic surface. In some embodiments the first surfacetreatment step 13 may remove an organic or hydrocarbon surface layer andmay also reduce and/or remove an oxide layer from the first metallicsurface. In some embodiments the first surface treatment step 13 mayprovide active sites on the first metallic surface. In some embodimentsthe substrate may be outgassed at the beginning of, or prior to step 13in order to remove, for example, any moisture from the substrate surfaceor inside the silicon containing material. In some embodiments the firstsurface treatment step 13 may not substantially damage or degrade thesecond surface, for example the first surface treatment step 13 may notprovide or form a significant amount of new surface groups or ligands onthe second surface.

In some embodiments step 14 of the selective deposition processcomprises selectively depositing a film on a substrate comprising afirst metal surface and a second surface comprising silicon using aplurality of deposition cycles. The cycle comprises: contacting thesubstrate with a first precursor comprising silicon or boron toselectively form a layer of first material comprising Si or B over thefirst metal surface relative to the second surface comprising silicon;and converting the first material to a second metallic material byexposing the substrate to a second precursor comprising metal. Theselective deposition step 14 involves forming a greater amount ofmaterial on the first metal surface relative to the second surfacecomprising silicon. The selectivity can be expressed as the ratio ofmaterial formed on the first surface to amount of material formed on thefirst and second surfaces combined. For example, if a process deposits10 nm of W on a first copper surface and 1 nm on a second silicon oxidesurface, the process will be considered to have 90% selectivity.Preferably, the selectivity of the methods disclosed herein is aboveabout 80%, more preferably above 90%, even more preferably above 95%,and most preferably about 100%. In some cases the selectivity is atleast about 80%, which may be selective enough for some particularapplications. In some cases the selectivity is at least about 50%, whichmay be selective enough for some particular applications. In someembodiments, multiple deposition cycles are used to deposit material atstep 14. In some embodiments the selectively deposited film is ametallic layer. The metallic layer may be elemental metal. In someembodiments, the metallic layer can include additional elements, such asSi, B, N, and/or dopants. Thus, in some embodiments the metallic layeris a metal nitride or metal silicide. As used herein, “metallic”indicates that a film, reactant or other material comprises one or moremetals.

The substrate can comprise various types of materials. Whenmanufacturing integrated circuits, the substrate typically comprises anumber of thin films with varying chemical and physical properties. Forexample and without limitation, the substrate may comprise a siliconcontaining layer and a metal layer. In some embodiments the substratecan comprise metal carbide. In some embodiments the substrate cancomprise a conductive oxide.

Preferably the substrate has a first surface comprising a metal,referred to herein as the first metal surface or first metallic surface.In some embodiments the first surface is essentially an elemental metal,such as Cu or Co. In some embodiments the first surface comprises ametal nitride. In some embodiments the first surface comprises atransition metal. The transition metal can be selected from the group:Ti, V, Cr, Mn, Nb, Mo, Ru, Rh, Pd, Ag, Au, Hf, Ta, W, Re, Os, Ir and Pt.In some embodiments the first surface preferably comprises copper. Insome embodiments the first surface comprises cobalt. In some embodimentsthe first surface comprises tungsten. In some embodiments the firstsurface may comprise a native oxide of a metal, for example the firstsurface may comprise tungsten oxide. In some embodiments the firstsurface may comprise a seam, gap, or space, and the selective depositionprocess closes or substantially fills the seam, gap, or space of thefirst surface. In some embodiments the first surface comprises a noblemetal. The noble metal can be selected from the group: Au, Pt, Ir, Pd,Os, Ag, Re, Rh, and Ru.

In some embodiments the second surface is a dielectric surface. In someembodiments the second surface is a silicon containing surface, referredto herein as the second silicon containing surface or second surfacecomprising silicon. In some embodiments, the silicon containing surfacecomprises, for example, SiO₂. In some embodiments the second surface maycomprise silicon oxide, silicon nitride, silicon carbide, siliconoxynitride, silicon dioxide, or mixtures thereof. In some embodimentsthe material comprising the second surface is a porous material. In someembodiments the porous material contains pores which are connected toeach other, while in other embodiments the pores are not connected toeach other. In some embodiments the second surface comprises a low-kmaterial, defined as an insulator with a dielectric value below about4.0. In some embodiments the dielectric value of the low-k material isbelow about 3.5, below about 3.0, below about 2.5 and below about 2.3.In some embodiments the second surface may comprise an organosilicatesurface, for example a silicon containing surface having organic surfacegroups, such as —CH_(x), surface groups. In some embodiments the secondsurface may comprise SiOCH.

The precursors employed in the processes disclosed herein may be solid,liquid or gaseous material under standard conditions (room temperatureand atmospheric pressure), provided that the precursors are in vaporphase before being conducted into the reaction chamber and contactedwith the substrate surface. Plasma conditions can also be used. Thus,plasma can be formed from the vapor phase reactants or precursors insome embodiments. “Pulsing” a vaporized precursor onto the substratemeans that the precursor vapor is conducted into the chamber for alimited period of time. Typically, the pulsing time is from about 0.05to 10 seconds. However, depending on the substrate type and its surfacearea, the pulsing time may be even higher than 10 seconds. Pulsing timescan be on the order of minutes in some cases. In some cases to ensurefull saturation of reactions, the precursor might be supplied inmultiple shorter pulses rather than in one longer pulse.

The mass flow rate of the precursors can also be determined by theskilled artisan. In one embodiment, for deposition on 300 mm wafers theflow rate of precursors is preferably between about 1 and 2000 sccmwithout limitation. In some embodiments the flow rate may be betweenabout 50 sccm and about 1500 sccm, between about 100 sccm and about 1000sccm, or between about 200 sccm and about 500 sccm.

The pressure in the reaction chamber is typically from about 0.01 toabout 50 mbar. In some embodiments the pressure may be between about 0.1mbar and about 20 mbar, or between about 1 mbar and about 10 mbar.However, in some cases the pressure will be higher or lower than thisrange, as can be readily determined by the skilled artisan.

Chamber Passivation

Referring again to FIG. 1, in some embodiments it may be desirable forthe reaction chamber or chambers in which a selective deposition processwill be carried out to be passivated at step 11 prior to selectivelydepositing a metallic film at step 14. In some embodiments the reactionchamber passivation step 11 may enable selective deposition, improveselectivity, and/or increase the number of cycles before selectivity islost during a selective deposition process, for example a metallic filmselective deposition process as described herein.

In some embodiments a selective deposition process for selectivedepositing a film on the first surface of a substrate, for example ametallic surface, relative to a second surface, for example a siliconcontaining surface can generate reactive byproducts which can rapidlydamage the second surface. The reactive byproducts may provide activesites on the second surface, resulting in a loss of selectivity. In someembodiments unwanted deposition may occur on reaction chamber surfaces,thereby leading to an increased amount of reactive byproducts in thereaction chamber over a selective deposition process wherein depositionoccurs primarily on the substrate. In order to reduce the amount ofunwanted deposition on chamber surfaces, for example the interiorsurfaces of the reaction chamber, and consequently reduce the amount ofreactive byproducts generated by the selective deposition process it isdesirable to passivate these chamber surfaces against deposition.

For example, in some embodiments a W selective deposition process maygenerate reactive byproducts having the formula SiF_(x), where x=1-4. Insome embodiments where the reaction chamber has not been passivated,unwanted W deposition may occur on chamber surfaces, thereby producingan undesirable amount of SiF_(x) byproducts. In some embodiments where areaction chamber has been passivated, W deposition may occur primarilyon the first surface of the substrate and may not occur, or may occur toa lesser extent on unwanted chamber surfaces, thereby leading to areduction in the amount of SiF_(x) byproducts generated during theselective deposition process relative to a W selective depositionprocess wherein the reaction chamber had not been passivated.

In some embodiments the reaction chamber passivation step 11 isperformed when there is no wafer or substrate in the reaction chamber.Therefore, in some embodiments a substrate, for example a substratecomprising a first metallic surface and a second silicon containingsurface is not subjected to the reaction chamber passivation step 11. Insome embodiments the substrate may be subjected to other processingbefore, during, or after the reaction chamber passivation step 11.

In some embodiments the reaction chamber passivation step 11 may berepeated after a selective deposition process has been performed at step14. In some embodiments the reaction chamber passivation step 11 may berepeated after every one, two, three, or more selective deposition steps14 have been carried out. For example, in some embodiments the reactionchamber passivation step 11 may be repeated after every 1, 5, 10, 20,50, or more substrates, for example wafers, have been subjected toselective deposition step 14. In some embodiments the reaction chamberpassivation step 11 may be repeated after a certain number of cycles ofselective deposition step 14 have been performed. In some embodimentsthe reaction chamber passivation step 11 may be repeated after every 50,100, 150, or more selective deposition cycles. In some embodiments thesubstrate or substrates may remain in the reaction chamber, or may notbe present in the reaction chamber during the reaction chamberpassivation step 11.

In some embodiments a reaction chamber passivation step 11 may includeproviding a passivation layer or passivation material on chambersurfaces and other surfaces in which may be exposed to a precursor orreactant during the selective deposition step 14. In some embodimentsthe passivation material is deposited or formed on the interior surfaceof the reaction chamber, the chamber showerhead, and/or any other partsof the chamber which may be exposed to a precursor or reactant duringselective deposition step 14. In some embodiments the passivationmaterial may be deposited on any surface in the reaction chamber that isnot the substrate upon which selective deposition is desired to occur.In some embodiments the passivation material is a different materialthan the material being selectively deposited in step 14. In someembodiments a disposition process used to deposit the passivation layermay not be a selective deposition process.

In some embodiments reaction chamber passivation 11 can increase thenumber of consecutive cycles in which a desired level of selectivity ofa selective deposition process 14 is maintained. In some embodiments areaction chamber passivation process 11 can increase the number ofconsecutive cycles in which a desired level of selectivity of aselective deposition process 14 is maintained by more than about 50% ascompared to a reaction chamber that has not been subjected to anyreaction chamber passivation process 11. In some embodiments a reactionchamber passivation process 11 can increase the number of consecutivecycles in which a desired level of selectivity of a selective depositionprocess 14 is maintained by more than about 75%, more than about 100%,more than about 200%, more than about 400%, or more than about 900% ascompared to a reaction chamber that has not been subjected to anyreaction chamber passivation process 11. In some embodiments a reactionchamber passivation process 11 can increase the number of consecutivecycles in which a desired level of selectivity of a selective depositionprocess 14 is maintained by more than about 20 times as compared to areaction chamber that has not been subjected to any reaction chamberpassivation process 11.

In some embodiments a reaction chamber passivation process 11 canincrease the number of consecutive cycles in which a desired level ofselectively of a selective deposition process 14 is maintained, and thereaction chamber passivation process 11 can be repeated after a desirednumber of cycles in order to allow for additional consecutive cycles inwhich a desired level of selectively of a selective deposition process14 is maintained. That is, the reaction chamber passivation process 11can be performed after a desired number of consecutive cycles and beforethe selectivity of the selective deposition process has decreased tobelow a desired level in order to allow for additional consecutivecycles in which a desired level of selectivity of the selectivedeposition process is maintained. The reaction chamber passivation 11may be repeated any number of times after a desired number ofconsecutive cycles of a selective deposition process in order tomaintain the desired level of selectivity of the selective depositionprocess 14.

In some embodiments a previously deposited passivation layer or layersmay be etched, or at least partially removed from the interior surfacesof the reaction chamber prior to the deposition of a subsequentpassivation layer via a reaction chamber passivation process 11. In someembodiments a previously deposited passivation layer or layers may beetched or at least partially removed from the interior surfaces of thereaction chamber after the reaction chamber has been subjected to two ormore, five or more, or ten or more reaction chamber passivationprocesses 11. In some embodiments no etching or layer removal isperformed between the two or more, five or more, or ten or more reactionchamber passivation processes. In some embodiments the reaction chambermay then be subjected to a reaction chamber passivation process 11 afterthe previously deposited passivation layer or layers have been etched orat least partially removed from the interior surfaces of the reactionchamber.

In some embodiments reaction chamber passivation 11 can increase theduration for which a desired level of selectivity of a selectivedeposition process 14 is maintained. In some embodiments a reactionchamber passivation process 11 can increase the duration for which adesired level of selectivity of a selective deposition process 14 ismaintained by more than about 50%, more than about 75%, more than about100%, more than about 200%, more than about 400%, or more than about900% as compared to a reaction chamber that has not been subjected toany reaction chamber passivation process 11. In some embodiments areaction chamber passivation process 11 can increase the duration forwhich a desired level of selectivity of a selective deposition process14 is maintained by more than about 20 times as compared to a reactionchamber that has not been subjected to any reaction chamber passivationprocess 11.

In some embodiments reaction chamber passivation 11 can increase thenumber of substrates, for example, wafers, for which a desired level ofselectivity of a selective deposition process 14 is maintained. That is,reaction chamber passivation 11 can increase the number of wafers onwhich selective deposition can be carried out simultaneously whilemaintaining a desired level of selectivity. In some embodiments areaction chamber passivation process 11 can increase the number ofsubstrates for which a desired level of selectivity of a selectivedeposition process 14 is maintained by more than about 2 times, morethan about 5 times, more than about 10 times, more than about 20 times,or more than about 50 times as compared to a reaction chamber that hasnot been subjected to any reaction chamber passivation process 11.

In some embodiments a reaction chamber passivation process 11 can extendthe number of deposition cycles which can be performed in the reactionchamber before maintenance is required. In some embodiments a reactionchamber passivation process 11 can extend the number of depositioncycles which can be performed in the reaction chamber before maintenanceis required by more than about 50%, more than about 75%, more than about100%, more than about 200%, more than about 400%, more than about 900%,or more than about 20 times as compared to a reaction chamber that hasnot been subjected to any reaction chamber passivation process 11

In some embodiments during a selective deposition process, material maybe deposited on interior surfaces of the reaction chamber. Thisdeposited material may flake off and interfere with selectivedeposition, or may provide for reactive sites such that an undesirablyhigh amount of undesirable reaction byproducts may be generated during aselective deposition process. Thus, it may be necessary to removedeposited material from the interior surfaces of the reaction chamberperiodically. In some embodiments a reaction chamber passivation process11 can extend the number of deposition cycles which can be performed inthe reaction chamber before etching, for example in-situ etching, mustbe performed to obtain or maintain a desired level of selectivity. Insome embodiments a reaction chamber passivation process 11 can extendthe number of deposition cycles which can be performed in the reactionchamber before etching, for example in-situ etching, must be performedto obtain or maintain a desired level of selectivity by more than about50%, more than about 75%, more than about 100%, more than about 200%,more than about 400%, more than about 900%, or more than about 20 timesas compared to a reaction chamber that has not been subjected to anyreaction chamber passivation process 11.

In some embodiments the passivation layer deposited or formed during thereaction chamber passivation step 11 may comprise SiN. In someembodiments the passivation layer may comprise silicon oxide, siliconnitride, silicon carbide, silicon oxynitride, or mixtures thereof. Insome embodiments the passivation layer may comprise a metal oxide. Insome embodiments the passivation layer may comprise any material otherthan pure metal or pure silicon. In some embodiments the passivationlayer is not a self-assembled monolayer (SAM) or a similar layerutilizing molecules similar to those used to form a SAM.

In some embodiments the passivation layer may be deposited or formed atstep 11 by a vapor deposition process. In some embodiments thedeposition process for forming the passivation layer may comprise avapor deposition process that is chemically driven. That is, thedeposition process for forming the passivation layer is a vapordeposition process that depends on one or more chemical reactions ofprecursors, and is not a physical vapor deposition process. For examplethe deposition process for forming or depositing the passivation layermay be a chemical vapor deposition (CVD) process, or atomic layerdeposition (ALD) process. In some embodiments the passivation layer maybe formed by a plasma enhanced ALD (PEALD) process or a plasma enhancedCVD (PECVD) process.

In some embodiments a deposition process for forming the passivationlayer may comprise between 1 and 10,000 deposition cycles, between 5 and5,000 deposition cycles, between 10 and 2,500 deposition cycles, orbetween 10 and 50 deposition cycles. In some embodiments the passivationlayer may have a thickness of from about 1 nm to about 1000 nm, fromabout 5 nm to about 500 nm, from about 10 nm to about 250 nm, or fromabout 40 nm to about 150 nm. In some embodiments, however, it may beuseful for the passivation layer to have a thickness of less than 1 nm.In some embodiments the passivation layer may have a thickness of lessthan about 200 nm, less than about 100 nm, less than about 50 nm andless than about 25 nm.

In some embodiments the deposition process for forming the passivationlayer may comprise an ALD type process comprising one or more depositioncycles, a deposition cycle comprising alternately and sequentiallyexposing or contacting the reaction chamber surfaces to a first vaporphase precursor and a second vapor phase precursor. In some embodimentsthe first vapor phase precursor and reaction byproducts, if any, may beremoved from the reaction chamber before exposing or contacting thereaction chamber surfaces to a second vapor phase precursor. In someembodiments the second vapor phase precursor and any reaction byproductsmay similarly be removed from the reaction chamber before subsequentlyexposing or contacting the reaction chamber surfaces to the first vaporphase precursor.

In some embodiments the deposition process for forming the passivationlayer may comprise a CVD type process wherein a first vapor phaseprecursor and a second vapor phase precursor are conducted into areaction chamber in simultaneous or overlapping pulses, wherein theprecursors react and/or decomposed on the chamber surfaces to form thepassivation layer.

In some embodiments the deposition process for forming the passivationlayer may comprise a PECVD type process wherein a first vapor phaseprecursor and a second vapor phase precursor are conducted into areaction chamber in simultaneous or overlapping pulses, and wherein aplasma is generated in the reaction chamber. The precursors react and/ordecompose in the plasma and/or on the chamber surfaces to form thepassivation layer. In some embodiments a plasma may be generatedremotely and introduced into the reaction chamber.

In some embodiments a deposition process for forming a passivation layercomprising SiN may be a PECVD process. In some embodiments a PECVDdeposition process may utilize a vapor phase silicon precursor and avapor phase nitrogen precursor. In some embodiments the siliconprecursor and the nitrogen precursor may be provided into the reactionchamber together or in overlapping pulses. In some embodiments a plasmais generated in the reaction chamber and the silicon and nitrogenprecursors react and/or decompose to form a SiN passivation layer on thechamber surfaces. In some embodiments a plasma may be generated remotelyand introduced into the reaction chamber.

In some embodiments a deposition process for forming a passivation layercomprising silicon, such as SiN, may utilize a silicon precursor and oneor more additional precursors, such as a nitrogen precursor. In someembodiments a deposition process for forming a passivation layer mayutilize nitrogen precursor. In some embodiments the silicon precursorused in the passivation layer deposition process may comprise a silane,for example silane, disilane, or trisilane. In some embodiments thenitrogen precursor may atomic nitrogen, nitrogen radicals, nitrogenplasma, or combinations thereof. In some embodiments the nitrogenprecursor may further comprise atomic hydrogen, hydrogen radicals,hydrogen plasma, or combinations thereof. In some embodiments thenitrogen precursor may comprise plasma generated from N₂. In someembodiments the nitrogen precursor may comprise a plasma generated fromN₂ and H₂ In some embodiments the nitrogen precursor may comprise plasmagenerated from N₂ and a noble gas, for example argon. In someembodiments the nitrogen precursor may comprise plasma generated fromN₂, H₂, and a noble gas, for example argon. In some embodiments thesilicon precursor and the nitrogen precursor may be provided into thereaction chamber separately in an ALD type reaction or may be providedinto the reaction chamber together or in over-lapping pulses in a CVDreaction.

In some embodiments a deposition process for forming a passivationlayer, for example a passivation layer comprising silicon and nitrogensuch as SiN, may comprise one or more deposition cycles, a depositioncycle comprising alternately and sequentially exposing or contacting thereaction chamber surfaces to a first vapor phase precursor, a secondvapor phase precursor, and a third vapor phase precursor. In someembodiments the first vapor phase precursor may comprise a silane; thesecond vapor phase precursor may comprise a metal halide; and the thirdvapor phase precursor may comprise an aminosilane. In some embodimentsthe first vapor phase precursor may comprise disilane; the second vaporphase precursor may comprise WF₆; and the third vapor phase precursormay comprise trimethyl(dimethylamino)silane.

The terms first, second, and third precursor are used herein forreference only and the skilled artisan will understand that a depositioncycle may begin with exposure of the reaction chamber surfaces to any ofthe first, second, or third vapor phase precursor. In some embodimentsthe first vapor phase precursor may contact the substrate prior to thesecond or third vapor phase precursors. In some embodiments the secondvapor phase precursor may contact the substrate after the first vaporphase precursor and before the third vapor phase precursor. In someembodiments the third vapor phase precursor may contact the substrateafter both the first and second vapor phase precursors. In someembodiments the order in which the first, second, and third vapor phaseprecursors may be different. In some embodiments two, three, or moreprecursors may be provided together or at least in partially overlappingpulses without regard for being referred to as the first, second, third,etc. precursor. Further, the reaction chamber surfaces may bealternately and sequentially contacted with the vapor phase precursorsin any order as determined by the skilled artisan. For example, thechamber surfaces may be contacted with the third vapor phase precursorprior to contacting the surfaces with the second vapor phase precursorin a given deposition cycle.

In some embodiments a passivation layer deposition process utilizing afirst, second, and third vapor phase precursors may comprise one or moredeposition cycles, three or more deposition cycles, five or moredeposition cycles or ten or more deposition cycles, 25 or moredeposition cycles and in some instances less than or equal to 50deposition cycles.

In some embodiments the passivation layer deposited by a passivationlayer deposition process utilizing a first, second, and third vaporphase precursor is deposited after every selective deposition process14, or after every substrate, for example a wafer, which has beensubjected to a selective deposition process 14. That is, after aselective deposition process the substrate may be removed from thereaction chamber and an additional passivation layer may be deposited bya passivation layer deposition process. In some embodiments anadditional passivation layer is deposited by a passivation layerdeposition process after every substrate that has been subjected to aselective deposition process.

In some embodiments the passivation layer deposited by a passivationlayer deposition process utilizing a first, second, and third vaporphase precursor is deposited after more than every two substrates, morethan every four substrates, more than every nine substrates, or morethan every 19 substrates which have been subjected to a selectivedeposition process 14.

In some embodiments a deposition process for forming the passivationlayer may be carried out at a similar or the same reaction chamberpressure and temperature as a selective deposition process as describedherein. In some embodiments the flow rates of the vapor phase precursorsused in the passivation layer deposition process may be similar or thesame as the precursor flow rates used in a selective deposition processas described herein.

In some embodiments a passivation layer may be deposited at atemperature of less than about 400° C. In some embodiments a passivationlayer may be deposited at a temperature of less than about 250° C. Insome embodiments a passivation layer may be deposited at a temperatureof less than about 150° C. In some embodiments the passivation layer maybe deposited at a temperature of less than about 100° C.

In some embodiments the passivation layer may be deposited at, forexample, from about 20° C. to about 250° C., from about 30° C. to about200° C., or from about 40° C. to 150° C. In some embodiments thepassivation layer may be deposited at about the same temperature atwhich a subsequent selective deposition process may be performed.

In some embodiments the chamber surfaces onto which the passivationlayer is deposited may optionally be cleaned prior to depositing thepassivation layer. In some embodiments the chamber surfaces may becleaned by exposing the chamber surfaces to a plasma. For example, insome embodiments the reaction chamber may be cleaned by a processcomprising exposing the reaction chamber to radicals comprisingfluorine, such as NF₃-based radicals.

In some embodiments a metal oxide passivation layer may be formed by avapor deposition process, for example an ALD, CVD, PEALD, or PECVDprocess. In some embodiments a deposition process for forming thepassivation layer may comprise between 1 and 10,000 deposition cycles,between 5 and 5,000 deposition cycles, between 10 and 2,500 depositioncycles, or between 10 and 50 deposition cycles.

In some embodiments the passivation layer may comprise a metal oxide. Insome embodiments the passivation layer may comprise a transition metaloxide. In some embodiments the passivation layer may comprise, forexample, tantalum oxide (Ta₂O₅), titanium oxide (TiO₂), niobium oxide(Nb₂O₅), zirconium oxide (ZrO₂), hafnium oxide (HfO₂), tungsten oxide(WO_(x)), molybdenum oxide (MoO_(x)), or vanadium oxide (VO_(x)). Insome embodiments a passivation layer comprising a transition metal oxidemay be formed by a deposition process comprising one or more depositioncycles comprising alternately and sequentially exposing or contactingthe reaction chamber surfaces to a first vapor phase precursor and asecond vapor phase precursor. In some embodiments the deposition processmay be an ALD, CVD, PEALD, or PECVD process. In some embodiments thefirst vapor phase precursor may comprise a transition metal. In someembodiments the first vapor phase precursor may comprise a metal halideor an organometallic compound. In some embodiments the second vaporphase precursor may comprise oxygen. In some embodiments the secondvapor phase precursor may be an oxygen reactant or oxygen source. Insome embodiments the second vapor phase precursor may comprise O₃, H₂O,H₂O₂, oxygen atoms, oxygen plasma, oxygen radicals, or combinationsthereof.

In some embodiments a passivation layer comprising Al₂O₃ may be formedby a deposition process comprising one or more deposition cyclescomprising alternately and sequentially exposing or contacting thereaction chamber surfaces to a first vapor phase precursor comprisingaluminum and a second vapor phase precursor comprising oxygen. In someembodiments the first vapor phase precursor comprising aluminum maycomprise an organometallic compound comprising aluminum, for exampletrimethylaluminum (TMA). In some embodiments the second vapor phaseprecursor comprising oxygen may comprise O₃, H₂O, H₂O₂, oxygen atoms,oxygen plasma, oxygen radicals, or combinations thereof. Additionally,in some embodiments the first and second vapor phase precursors may beprovided in any order as can be readily determined by one of skill inthe art. In some embodiments the first and second vapor phase precursorsmay be provided together or at least in partially overlapping pulses,such as in a CVD process.

In some embodiments a metallic material may be deposited or formed onchamber surfaces by a vapor deposition process, for example by achemical vapor deposition (CVD), or atomic layer deposition (ALD)process. In some embodiments a metallic material may comprise antimony,for example elemental antimony. In some embodiments the passivationlayer may be formed by a plasma enhanced ALD (PEALD) process. In someembodiments a deposition process for forming the passivation layer maycomprise between 1 and 10,000 deposition cycles, between 5 and 5,000deposition cycles, between 10 and 2,500 deposition cycles, or between 10and 50 deposition cycles.

In some embodiments the metallic material may then be oxidized to form ametal oxide passivation layer. In some embodiments the metallic materialmay be oxidized by exposing the metallic material to an oxygen reactant.In some embodiments the oxygen reactant may comprise oxygen, oxygenatoms, oxygen radicals, oxygen plasma, or combinations thereof. Forexample, in some embodiments an oxygen reactant may comprise O₃, H₂O,H₂O₂, oxygen atoms, oxygen plasma, oxygen radicals, or combinationsthereof. In some embodiments the metallic material may be subjected toan oxidation process that comprises at least one step of exposing themetallic material to an oxidant, or oxygen reactant. In some embodimentsan oxidation process may comprise exposing the metallic material to twoor more oxidants or oxygen reactants in two or more steps. In someembodiments the two or more oxidants or oxygen reactants may bedifferent oxidants or oxygen reactants. In some embodiments the two ormore exposure steps may be separated by a purge or oxidant removal step.In some embodiments exposing the metallic material to more than oneoxidant or oxygen reactant may desirably result in a greater amount ofoxidation of the metallic material than exposure to one oxidant oroxygen reactant.

In some embodiments the passivation layer may be formed on the chambersurfaces by oxidizing metallic material that has been deposited on thechamber surfaces during a prior deposition process. In some embodimentswhere selective deposition step 14 has previously been carried out in areaction chamber, the reaction chamber passivation step 11 may compriseoxidizing any metallic material deposited on chamber surfaces during theselective deposition step 14 to for a metal oxide passivation layer. Insome embodiments the metallic material may be oxidized by exposing themetallic material to an oxygen precursor. In some embodiments the oxygenprecursor may comprise oxygen, oxygen atoms, oxygen radicals, oxygenplasma, or combinations thereof.

For example W deposited on the chamber surfaces during a prior Wselective deposition process may be oxidized to form a chamberpassivation layer. In some embodiments a metallic material is depositedon the chamber surfaces by a deposition process that is not used todeposit material on a substrate or wafer in the reaction chamber.

Silicon Containing Surface Treatment

As shown in FIG. 1 and in some embodiments, the silicon containingmaterial on which deposition is to be avoided can be treated at step 12.For example, in some embodiments the silicon containing material may betreated after a surface cleaning and prior to deposition. In someembodiments, a silicon containing surface can be treated to enhance theselectivity of the deposition process by decreasing the amount ofmaterial deposited on the silicon containing surface, for example bypassivating the silicon containing surface. In some embodiments thetreatment is intended to restore the silicon containing layer and not toblock deposition on the silicon containing layer.

In some embodiments the silicon containing surface is a low-k surface,which has been outgassed to remove moisture absorbed from theatmosphere.

In some embodiments the treatment of the silicon containing material isa dielectric restoration step. Different kinds of silicon containingmaterial restoration steps can be performed before the selectivedeposition and after the surface has been cleaned (if carried out).

In some embodiments the silicon containing surface is treated bycontacting the silicon containing surface with one or more silanes, suchas disilane. In some embodiments the silicon containing surface istreated with trimethylchlorosilane (CH₃)₃SiCl (TMCS) or with other typeof alkylhalosilanes having formula R_(3-x)SiX_(x), wherein x is from 1to 3 and each R can independently be selected to be C1-C5 hydrocarbon,such as methyl, ethyl, propyl or butyl, preferably methyl, and X ishalide, preferably chloride. U.S. Pat. No. 6,391,785 discloses varioussurface modifications and treatments and is incorporated herein in itsentirety. In some embodiments any of the surface modifications ortreatments disclosed in U.S. Pat. No. 6,391,785 can be used in themethods disclosed herein.

In some embodiments the silicon containing surface is contacted with,for example, trimethyl(dimethylamino)silane. In some embodiments thesilicon containing surface is contacted with an alkylaminosilane havingthe formula (R^(I))₃Si(NR^(II)R^(III)), wherein R^(I) is a linear orbranched C1-C5 alkyl group or a linear or branched C1-C4 alkyl group,R^(II) is a linear or branched C1-C5 alkyl group, a linear or branchedC1-C4 alkyl group, or hydrogen, and R^(III) is a linear or branchedC1-C5 alkyl group or a linear or branched C1-C4 alkyl group.

In some embodiments the silicon containing surface is contacted with asilane having the general formula (R^(I))₃SiA, wherein R^(I) is a linearor branched C1-C5 alkyl group or a linear or branched C1-C4 alkyl group,and A is any ligand which is reactive with the silicon containingsurface. That is, the silane bonds to the surface through ligand A, orligand A forms an bond to the surface but then ligand A may migrate awayfrom the surface and/or silane.

In some embodiments, the restoration chemical is selected from thesilane family and has the chemical formula Si_(n)H_(2n+2) (n is equal toor greater than 1), or the cyclic silane family and has the chemicalformula Si_(n)H_(2n) (n is equal to or greater than 3). In someembodiments the restoration chemical is a silicon source comprisingsilane, disilane, or trisilane. In some embodiments the silane isdisilane Si₂H₆ or trisilane Si₃H₈. In some embodiments the siliconsource can be selected from silane compounds having the formula:SiH_(x)L_(y), where L is a ligand selected from the groups including:alkyl, alkenyl, alkynyl, alkoxide, and amine. In some cases L is aligand selected from the halide group: F, Cl, Br and I.

In some embodiments a silicon containing surface restoration step iscarried out prior to selective deposition by exposing the substrate toone or more restoration chemicals, such as Si₂H₆ or TMCS, at atemperature of about room temperature to about 150° C., or about 40° C.to about 130° C. In some embodiments a silicon containing surfacerestoration step may be carried out at a temperature of up to about 400°C., from about 25° C. to about 300° C., or from 30° C. to about 250° C.In some embodiments a restoration chemical, such as Si₂H₆, is providedto the reaction chamber at a flow rate of about 5 to 100 sccm, or about30 to 60 sccm. In some embodiments the restoration chemical is providedto the reaction chamber for about 1 to 20 s, or about 1 to 10 s. In someembodiments a restoration chemical, such as TMCS, is provided in pulses.About 1-20 or about 1-10 pulses may be provided, for example with apulse and purge time of about 1 to 10 seconds each. In some embodimentsthe silicon containing surface restoration step may take place in asecond, separate reaction chamber from the reaction chamber in whichdeposition may be carried out.

While this step is called a surface restoration step, and the chemicalsused are called restoration chemicals, these designations are usedherein for simplicity and no particular restorative function is implied.Thus, in some embodiments the treatment and/or chemicals may not fullyor even partially restore a silicon containing surface.

If the silicon containing surface is damaged, it may also be restoredafter selective deposition steps by conducting a surface restorationstep.

Some silicon containing materials can have porous structures. In orderto avoid diffusion, etching, and other undesirable processes the porescan be sealed or terminated with protective groups prior to beginningthe deposition process. Thus, in some embodiments a porous siliconcontaining material can be treated to seal the pores or terminate with aprotective group prior to beginning the selective deposition. In someembodiments the porous silicon containing material is treated prior toproviding a metal reactant.

In some embodiments pores may be sealed by forming Si(R^(I))₃ groups onthe silicon containing surface, wherein R^(I) may be a linear orbranched C1-C5 alkyl group or a linear or branched C1-C4 alkyl group. Insome embodiments the pores are sealed via silylation, i.e., forming—Si(CH₃)₃ groups on the silicon containing surface, for example a low-kor SiO₂ surface. Etching can in part be avoided by silylation prior tointroducing metal fluoride or other reactants. Silylation can also beused to block the pores to avoid reactant penetration into the siliconcontaining material. In some embodiments silylation is accomplishedthrough the reaction of a silicon compound, for instance Cl—Si(CH₃)₃,with an Si—OH terminated surface of a silicon containing material:Si-OH+Cl—Si(CH₃)₃→Si—O—Si(CH₃)₃+HCl. Thus, in some embodiments anappropriate surface termination is formed prior to providing the siliconcompound. Also the use of silicon compounds with longer carboncontaining ligands is possible.

Methods for sealing the pores are disclosed, for example, in U.S. Pat.No. 6,759,325. The disclosure of sealing methods in U.S. Pat. No.6,759,325 is hereby incorporated by reference in its entirety.

In some embodiments an organic layer can be formed by ALD on the siliconcontaining material prior to deposition to block the pores and to makethe silicon containing surface more resistant to metal fluorides.

In some embodiments where the selectivity is imperfect or a higherselectivity is desired, the surface can be treated after selectivedeposition, for example using an isotropic selective metal etch, toremove material from the insulator surface without fully removingmaterial from the metallic surface. For example, HCl vapor or a wet etchcan be used.

First Metallic Surface Treatment

In some embodiments the substrate may be subjected to a process forremoving a surface layer from a metallic surface as described herein.For example, as described above, a substrate comprising at least a firstmetallic surface may be subjected to a process for a removing a surfacelayer therefrom as described herein prior to selectively depositing athin film thereon. In some embodiments the substrate may be subjected toa process for removing a surface layer from the first metallic surfaceof the substrate in a reaction chamber that has been passivated asdescribed herein. However, in some other embodiments the substrate maybe subjected to a process for removing a surface layer from the firstmetallic surface of the substrate in a reaction chamber that has notbeen passivated.

As shown in FIG. 1 and according to some embodiments the substratesurface may optionally be cleaned or treated at step 13. For example,for embodiments when the first material is copper, the copper surfacecan be cleaned or reduced such that pure elemental copper is on thesubstrate surface. In some embodiments the first surface treatmentprocess may comprise a surface layer removal process as described hereinabove. For example, the first surface treatment process may remove asurface layer present on the first surface of the substrate in order toenable or enhance selective deposition thereon. In some embodiments thesurface layer that is removed may comprise a layer of organic material.That is, in some embodiments a first surface treatment process mayremove any organic material present on the first metallic surface. Forexample a first surface treatment process may remove an organicpassivation layer present on the first metallic surface. For example,the first surface treatment process may remove a benzotriazole (BTA)passivation layer from a copper surface. In some embodiments the firstsurface treatment process may remove any organic and/or hydrocarbonlayer that may be present on the first metallic surface.

In some embodiments the first surface treatment process may reduce asurface layer or portion of a surface layer present on the firstmetallic surface of the substrate. In some embodiments the first surfacetreatment process may reduce and/or remove any oxide surface layerpresent on the first metallic surface. In some embodiments the firstsurface treatment process may reduce and/or remove any native oxidelayer that may be present on the first metallic surface. In someembodiments the first surface treatment process may provide active siteson the first metallic surface, for example by reducing and/or removing asurface layer or portion of a surface layer present on the firstmetallic surface. In some embodiments the oxide layer may be partiallyremoved and the remaining material comprises the oxide layer may bereduced by the first surface treatment process. That is, in someembodiments a portion of the oxide layer may be removed by the firstsurface treatment process, while any remaining oxide layer may bereduced by the first surface treatment process. In some embodimentssubstantially all of an oxide surface layer may be removed by the firstsurface treatment process. In some embodiments substantially all of anoxide surface layer may be reduced by the first surface treatmentprocess.

As used herein, the term reduce may refer to the chemical conversion ofan oxide material to its non-oxide form. That is, when a metal oxidematerial is reduced, it is chemically converted to the metal of themetal oxide. For example a copper oxide layer may be present on a firstmetallic surface comprising copper and the first surface treatmentprocess may reduce the copper oxide layer such that it is converted tometallic copper. In some embodiments the surface layer may comprise bothan organic surface layer and an oxide layer underlying the organicsurface layer. In some embodiments where the first metallic surface maycomprise a surface layer comprising an organic surface layer and anoxide layer underlying the organic surface layer the first surfacetreatment process may remove the organic surface layer and may alsoreduce and/or remove the oxide layer, thereby providing a clean firstmetallic surface.

The first surface treatment process can be done in any of a variety ofmethods, for example using a chemical such as citric acid or usingplasma. For example, the substrate surface may be cleaned or treatedusing a plasma generated from a gas, such as a gas comprising hydrogen,including H₂, NH₃, and/or other component gases. In some embodiments HCltreatment is used as the first surface treatment method. In someembodiments the first surface treatment process comprises exposing thesubstrate to a treatment reactant, for example formic acid. Other firstsurface treatment methods are also possible. The specific first surfacetreatment method to be used in any particular case can be selected basedon a variety of factors such as the materials and the depositionconditions, including, for example, the types of materials on thesubstrate surface.

In some cases a first material on which selective deposition is desired,such as copper, is passivated. The passivation may be the result of anintentional treatment of the substrate to form the passivation layer, ormay result from the processing conditions, such as exposure to oxygenduring transport of the substrate.

The surface(s) of the substrate may be passivated, for example, prior totransfer from one reaction space to another. In some embodiments thesurface of the first material may be passivated against oxidation in airusing any of a variety of known passivation chemicals. In someembodiments in which selective deposition on Cu is desired, the Cusurface may be passivated, for example with BTA. This passivation can beremoved with the first surface treatment methods described herein.

In some embodiments the first surface treatment process comprisesexposing the substrate to a treatment reactant. In some embodiments thetreatment reactant is a vapor phase organic reactant. In someembodiments the treatment reactant may contain at least one alcoholgroup and may be preferably selected from the group consisting ofprimary alcohols, secondary alcohols, tertiary alcohols, polyhydroxyalcohols, cyclic alcohols, aromatic alcohols, and other derivatives ofalcohols.

Preferred primary alcohols have an —OH group attached to a carbon atomwhich is bonded to another carbon atom, in particular primary alcoholsaccording to the general formula (I):R¹—OH  (I)

wherein R¹ is a linear or branched C₁-C₂₀ alkyl or alkenyl groups,preferably methyl, ethyl, propyl, butyl, pentyl or hexyl. Examples ofpreferred primary alcohols include methanol, ethanol, propanol, butanol,2-methyl propanol and 2-methyl butanol.

Preferred secondary alcohols have an —OH group attached to a carbon atomthat is bonded to two other carbon atoms. In particular, preferredsecondary alcohols have the general formula (II):

wherein each R¹ is selected independently from the group of linear orbranched C₁-C₂₀ alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. Examples of preferred secondary alcoholsinclude 2-propanol and 2-butanol.

Preferred tertiary alcohols have an —OH group attached to a carbon atomthat is bonded to three other carbon atoms. In particular, preferredtertiary alcohols have the general formula (III):

wherein each R¹ is selected independently from the group of linear orbranched C₁-C₂₀ alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. An example of a preferred tertiaryalcohol is tert-butanol.

Preferred polyhydroxy alcohols, such as diols and triols, have primary,secondary and/or tertiary alcohol groups as described above. Examples ofpreferred polyhydroxy alcohol are ethylene glycol and glycerol.

Preferred cyclic alcohols have an —OH group attached to at least onecarbon atom which is part of a ring of 1 to 10, more preferably 5-6carbon atoms.

Preferred aromatic alcohols have at least one —OH group attached eitherto a benzene ring or to a carbon atom in a side chain.

Preferred treatment reactants containing at least one aldehyde group(—CHO) are selected from the group consisting of compounds having thegeneral formula (V), alkanedial compounds having the general formula(VI), and other derivatives of aldehydes.

Thus, in one embodiment preferred treatment reactants are aldehydeshaving the general formula (V):R³—CHO  (V)

wherein R³ is selected from the group consisting of hydrogen and linearor branched C₁-C₂₀ alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. More preferably, R³ is selected from thegroup consisting of methyl or ethyl. Examples of preferred compoundsaccording to formula (V) are formaldehyde, acetaldehyde andbutyraldehyde.

In another embodiment preferred treatment reactants are aldehydes havingthe general formula (VI):OHC—R⁴—CHO  (VI)

wherein R⁴ is a linear or branched C₁-C₂₀ saturated or unsaturatedhydrocarbon. Alternatively, the aldehyde groups may be directly bondedto each other (R⁴ is null).

Preferred treatment reactants containing at least one —COOH group arepreferably selected from the group consisting of compounds of thegeneral formula (VII), polycarboxylic acids, and other derivatives ofcarboxylic acids.

Thus, in one embodiment preferred treatment reactants are carboxylicacids having the general formula (VII):R⁵—COOH  (VII)

wherein R⁵ is hydrogen or linear or branched C₁-C₂₀ alkyl or alkenylgroup, preferably methyl, ethyl, propyl, butyl, pentyl or hexyl, morepreferably methyl or ethyl. In some embodiments, R⁵ is a linear orbranched C₁-C₃ alkyl or alkenyl group. Examples of preferred compoundsaccording to formula (VII) are formic acid, propanoic acid and aceticacid, most preferably formic acid (HCOOH).

In some embodiments the first surface treatment process is a process asdescribed in U.S. patent application Ser. No. 14/628,799, entitled“REMOVAL OF SURFACE PASSIVATION”, which is hereby incorporated byreference in its entirety.

In some embodiments, the first metallic surface of the substrate issubjected to a first surface treatment process comprising exposing thesubstrate to a plasma generated from a gas. In some embodiments thefirst surface treatment process may comprise exposing at least the firstsurface to the plasma. In some embodiments the first surface treatmentprocess may comprise exposing the first surface and the second surfaceto the plasma. Such a first surface treatment process may, for example,remove a passivation layer present on a first metallic surface, such asa Cu surface. Such a first surface treatment process may also, forexample, reduce or remove an oxide layer from the first metallicsurface, such as reducing or removing a copper oxide layer from a Cusurface

In some embodiments the first surface treatment process comprisesexposing the substrate to a plasma generated from a gas. In someembodiments the plasma may be generated from a gas consisting only ofAr. In some embodiments an Ar and H-containing plasma is used in thefirst surface treatment process. In some embodiments an Ar and H andN-containing plasma is used in the first surface treatment process. Itmay be noted that instead of Ar, other noble gases, such as He, Ne, Kror Xe can be used in substantially same conditions. In some embodimentsmore than one type of plasma may be used. For example, one or more ofAr-containing plasma, Ar and H-containing plasma and Ar, H andN-containing plasma may be provided. That is, in some embodiments theplasma may be generated from a gas comprising Ar, H, and/or N containinggas or gases. In some embodiments Ar, or another noble gas, may be usedas a carrier gas for the component gases from which the plasma isgenerated. For example, in some embodiments where a plasma is generatedfrom a gas comprising H₂, Ar may be used as a carrier gas for the H₂.Accordingly, in some embodiments the plasma generated from the gascomprising H2 and a carrier gas may comprise H-plasma and Ar-plasma.

In some embodiments a plasma generated from a gas comprising H₂ can beused in the first surface treatment process. In some embodiments aplasma generated from a gas comprising ethanol can be used in the firstsurface treatment process. In some embodiments a plasma generated from agas comprising both H₂ and ethanol may be used in the first surfacetreatment process. In some embodiments, for example where the firstmetallic surface is a Cu surface, a plasma generated from a gascomprising H₂, ethanol, or H₂ and ethanol is preferably used in thefirst surface treatment process.

In some embodiments a plasma generated from a gas comprising NH₃ can beused in the first surface treatment process. In some embodiments aplasma generated from a gas comprising NH₃ and H₂ can be used in thefirst surface treatment process. In some embodiments, for example wherethe first metallic surface is a Co surface a plasma generated from a gascomprising NH₃ and H₂ is used in the first surface treatment process. Insome embodiments a plasma may be generated from a gas comprising NH₃ andH₂ where the ratio of NH₃ to H₂ is from about 1:100 to about 1:1,preferably from about 1:5 to about 1:20. In some embodiments the ratioof NH₃ to H₂ may be about 1:19, about 1:9, or about 1:5.

In some embodiments a plasma generated from a gas comprising one or moreorganic compounds can be used in the first surface treatment process. Insome embodiments a plasma generated from a gas comprising a compoundaccording to formulas (I)-(VII) above can be used in the first surfacetreatment process. In some embodiments a plasma generated from a gascomprising formic acid (HCOOH) can be used in the first surfacetreatment process. In some embodiments a plasma generated from a gascomprising carbolic acid can be used in the first surface treatmentprocess. In some embodiments a plasma generated from a gas comprisingHCOOH and NH₃ can be used in the first surface treatment process. Insome embodiments a plasma generated from a gas comprising HCOOH and H₂can be used in the first surface treatment process.

In some embodiments a plasma generated from a gas comprising HCOOH, NH₃,and H₂ can be used in the first surface treatment process. In someembodiments a plasma may be generated from a gas comprising HCOOH, NH₃,and H₂ where the ratio of HCOOH to NH₃ to H₂ is from about 1:1:5 toabout 1:1:20, or from about 1:1:9 to about 1:1:19. In some embodimentsthe ratio of HCOOH to NH₃ to H₂ is about 1:1:19.

In some embodiments the first surface treatment process may compriseexposing the substrate to a first treatment reactant followed byexposure to a second treatment reactant. In some embodiments the firsttreatment reactant may comprise O₃, atomic oxygen, oxygen radicals, oroxygen plasma. In some embodiments the second treatment reactant maycomprise atomic hydrogen, hydrogen radicals, or hydrogen plasma. In someembodiments the first treatment reactant may be removed from thereaction chamber prior to introducing the second treatment reactant. Insome embodiments exposure to the first treatment reactant may occur in afirst reaction chamber and exposure of the substrate to the secondtreatment reactant may occur in a second reaction chamber.

In some embodiments the first treatment reactant may remove any organicpassivation layer or hydrocarbons that may be present on the firstmetallic surface while the second treatment reactant may remove and/orreduce an oxide layer on the first metallic surface. For example, insome embodiments where the first metallic surface is a Co surface,exposure to O₃ may remove a naturally occurring hydrocarbon layer fromthe Co surface while subsequent exposure to H radicals may reduce a Cooxide layer present on the Co surface.

In some embodiments utilizing Ar-containing plasma, Ar may be provided,for example, from about 1 to about 3000 sccm, more preferably from about300 to about 1500 sccm, and most preferably from about 1000 to about1300 sccm. In some embodiments utilizing H-containing plasma, H₂ may beprovided, for example, from about 1 to about 500 sccm, more preferablyfrom about 10 to about 200 sccm, and most preferably from about 30 toabout 100 sccm. In some embodiments utilizing N-containing plasma, N₂ orNH₃ may be provided, for example, at about from about 1 to about 500sccm, more preferably from about 5 to about 200 sccm, and mostpreferably from about 5 to about 30 sccm. Similar conditions can be usedfor other types of plasma, for example ethanol or O-containing plasma.In some embodiments using a plasma generated from a gas comprisingHCOOH, the gas may be provided at a flow rate of about 1 sccm to about3000 sccm.

In some embodiments where a plasma is generated from a gas comprisingHCOOH, NH₃, and H₂ the gas may be provided at a flow rate of about fromabout 1 sccm to about 3000 sccm. In some embodiments where a plasma isgenerated from a gas comprising HCOOH, NH₃, and H₂ the gas may beprovided at a flow rate of about 1000 sccm. In some embodiments the flowrates discussed herein do not include the flow rate of any carrier gasthat may be used to provide the gas from which the plasma is generated.

In some embodiments plasma may be generated at a power of less thanabout 3000 Watts, for example about 1 to about 3000 W, about 1 to about1500 W, about 1 to 1000 W, about 1 to about 500 W, or about 1 to about200 W or less. In some embodiments the frequency of the RF power used togenerate the plasma may be from about 1 MHz to about 10 GHz, from about10 MHz to about 1 GHz, or from about 100 MHz to about 500 MHz.

In some embodiments the plasma or treatment reactant is provided forless than about 200 s, for example about 180 s or less, about 60 s orless, or about 30 s or less. However, in some embodiments the firstsurface treatment process may comprise exposing the substrate to theplasma or treatment reactant for up to 10 minutes or longer. Forexample, in some embodiments the substrate is exposed to the plasma ortreatment reactant from about 1 second to about 10 minutes, about 5seconds to about 5 minutes, about 10 seconds to about 1 minute, or about15 seconds to about 30 seconds. In some embodiments the substrate isexposed to the plasma or treatment reactant for from about 5 seconds toabout 30 seconds.

In some embodiments exposure of the substrate to a plasma or reactantcan be continuous, or split into several pulses. The number of necessarypulses is determined by the length of each of the pulses used to reachthe require total exposure time as determined by the skilled artisan.

Temperature during the surface treatment may be, for example, from aboutroom temperature to about 400° C., from about 100° C. to about 400° C.,from about 100° C. to about 300° C., 100° C. to about 200° C., or fromabout 100° C. to about 130° C. In some embodiments the substratetemperature during the first surface treatment may be about 150° C. Insome embodiments the substrate may be subjected to an outgassed in orderto remove, for example, moisture from the substrate surface of insidethe silicon containing material. In some embodiments the substrate maybe outgassed prior to subjecting the substrate to a first surfacetreatment process. In some embodiments the pressure of the gas fromwhich the plasma is generated in a first surface treatment process maybe from about 1 Pa to about 5000 Pa, from about 10 Pa to about 3000 Pa,from about 50 Pa to about 1000 Pa, from about 150 Pa to about 500 Pa, orabout 350 Pa.

In some embodiments, conditions for a first surface treatment processare selected such that etching of the second surface may be avoided orminimized. That is, in some embodiments the first surface treatmentprocess does not substantially damage or degrade the second surface. Asused herein with reference to the second surface, the terms damage ordegrade can refer to alterations to the second surface which may reducethe selectivity of a selective deposition process, such as the processesdescribed herein. For example, in a selective deposition process fordepositing a film on a first surface relative to the second surface,more material or particles of the deposited material may be deposited ona damaged or degraded second surface as compared to a second surfacethat has not been damaged or degraded. Accordingly, the presence ofdeposited material on the second surface after a selective depositionprocess for depositing a film on a first surface relative to the secondsurface as described herein may be indicative of a damaged or degradedsecond surface. In some embodiments the first surface treatment processdoes not reduce or eliminate the selectivity of a selective depositionprocess as compared to a similar selective deposition process that doesnot include a first surface treatment process. In some embodiments asignificant amount of new surface groups or ligands, that is, enough toreduce the selectivity of a selective deposition process, are not formedor adsorbed onto the second surface by a first surface treatmentprocess. In some embodiments the first surface treatment process doesnot significantly change the amount of material deposited on the secondsurface of the substrate by a selective deposition process as compartedto a similar selective deposition process that does not include a firstsurface treatment process.

A schematic diagram of an example substrate 20 comprising a firstmetallic surface 21 and second dielectric surface 22 prior to a firstsurface treatment process is illustrated in FIG. 2A according to someembodiments. The first metallic surface 21 comprises a metal oxide layer23 disposed thereon, for example a native metal oxide layer naturallyformed via exposure to an ambient environment. The first metallicsurface 21 also comprises an organic layer 25, for example an organicpassivation layer, such as a BTA layer, disposed over the metal oxidelayer 23.

The substrate 20 may then be subjected to a first surface treatmentprocess, as described herein and according to some embodiments. Forexample, the substrate 20, and consequently the first metallic surface21 and the second dielectric surface 22 may be exposed to a plasmagenerated from a gas, for example a gas comprising HCOOH, H₂, and NH₃.As shown in FIG. 2B, the first surface treatment process may remove theorganic layer 25 from the first metallic surface 21. The first surfacetreatment process may also remove and/or reduce the metal oxide layer 23from the first metallic surface 21, thereby leaving a clean firstmetallic surface 21. Additionally, as shown in FIG. 2B, the seconddielectric surface is not damaged or degraded by the first surfacetreatment process, and does not comprise a significant amount of new oradditional surface groups and/or ligands.

Selective Deposition

First Precursor

In some embodiments a first precursor is provided to the substrate suchthat a layer is selectively formed on a first metal surface of thesubstrate relative to a second silicon containing surface of thesubstrate. In some embodiments the first precursor preferably comprisessilicon or boron. In some embodiments a 0.05-4 nm thick layer of Si or Bis formed on the metal surface of the substrate. In some embodiments a0.1-2 nm thick layer of Si or B is formed on the metal surface of thesubstrate. In some embodiments less than 1 nm of Si or B can be used.Without being bound to a theory, it is believed that the metal surfaceon the substrate can catalyze or assist in the adsorption ordecomposition of the first precursor in comparison to the reactivity ofthe second surface. In some embodiments the formation of silicon orboron on the metal surface is self-limiting, such that up to a monolayeris formed upon exposure to the reactant. In some embodiments the siliconor boron source chemical can decompose on the copper or metal surface.

In some embodiments, the silicon source chemical is selected from thesilane family Si_(n)H_(2n+2) (n is equal to or greater than 1) or thecyclic silane family Si_(n)H_(2n) (n is equal to or greater than 3). Insome embodiments the silicon source comprises silane or disilane. Mostpreferably the silane is disilane Si₂H₆ or trisilane Si₃H₈. In someembodiments the silicon source can be selected from silane compoundshaving the formula: SiH_(x)L_(y), where L is a ligand selected from thegroups including: alkyl, alkenyl, alkynyl, alkoxide, and amine. In somecases L is a ligand selected from the halide group: F, Cl, Br and I.

In some embodiments the first precursor comprises boron. In someembodiments the first precursor is diborane (B₂H₆). Diborane has similarproperties to some of the silane based compounds. For example, diboranehas a lower decomposition temperature than disilane but similar thermalstability to trisilane (silcore).

Other precursors comprising boron could also be used. The availabilityof a vast number of boron compounds makes it possible to choose one withthe desired properties. In addition, it is possible to use more than oneboron compound. Preferably, one or more of the following boron compoundsis used:

Boranes according to formula I or formula II.B_(n)H_(n+x),  (I)

Wherein n is an integer from 1 to 10, preferably from 2 to 6, and x isan even integer, preferably 4, 6 or 8.B_(n)H_(m)  (II)

Wherein n is an integer from 1 to 10, preferably form 2 to 6, and m isan integer different than n, from 1 to 10, preferably from 2 to 6.

Of the above boranes according to formula I, examples includenido-boranes (B_(n)H_(n+4)), arachno-boranes (B_(n)H_(n+6)) andhyph-boranes (B_(n)H_(n+8)). Of the boranes according to formula II,examples include conjuncto-boranes (B_(n)H_(m)). Also, borane complexessuch as (CH₃CH₂)₃N—BH₃ can be used.

Borane halides, particularly fluorides, bromides and chlorides. Anexample of a suitable compound is B₂H₅Br. Further examples compriseboron halides with a high boron/halide ratio, such as B₂F₄, B₂Cl₄ andB₂Br₄. It is also possible to use borane halide complexes.

Halogenoboranes according to formula III.B_(n)X_(n)  (III)

Wherein X is Cl or Br and n is 4 or an integer from 8 to 12 when X isCl, or n is an integer from 7 to 10 when X is Br.

Carboranes according to formula IV.C₂B_(n)H_(n+x)  (IV)

Wherein n is an integer from 1 to 10, preferably from 2 to 6, and x isan even integer, preferably 2, 4 or 6.

Examples of carboranes according to formula IV include closo-carboranes(C₂B_(n)H_(n+2)), nido-carboranes (C₂B_(n)H_(n+4)) andarachno-carboranes (C₂B_(n)H_(n+6)).

Amine-borane adducts according to formula V.R₃NBX₃  (V)

Wherein R is linear or branched C1 to C10, preferably C1 to C4 alkyl orH, and X is linear or branched C1 to C10, preferably C1 to C4 alkyl, Hor halogen.

Aminoboranes where one or more of the substituents on B is an aminogroup according to formula VI.R₂N  (VI)

Wherein R is linear or branched C1 to C10, preferably C1 to C4 alkyl orsubstituted or unsubstituted aryl group.

An example of a suitable aminoborane is (CH₃)₂NB(CH₃)₂.

Cyclic borazine (—BH—NH—)₃ and its volatile derivatives.

Alkyl borons or alkyl boranes, wherein the alkyl is typically linear orbranched C1 to C10 alkyl, preferably C2 to C4 alkyl.

In some embodiments the first precursor comprises germanium. In someembodiments, the germanium source chemical is selected from the germanefamily Ge_(n)H_(2n+2) (n is equal to or greater than 1) or the cyclicgermane family Ge_(n)H_(2n) (n is equal to or greater than 3). In somepreferred embodiments the germanium source comprises germane GeH₄. Insome embodiments the germanium source can be selected from germanecompounds having the formula: GeH_(x)L_(y), where L is a ligand selectedfrom the groups including: alkyl, alkenyl, alkynyl, alkoxide, and amine.In some cases L is a ligand selected from the halide group: F, Cl, Brand I.

Metal Source Chemicals

Preferably the second reactant comprises a metal. In some embodimentsthe metal is a transition metal. The transition metal can be selectedfrom the group of: Ti, V, Cr, Mn, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,Os, Ir and Pt. In some embodiments the second reactant comprises W, Ta,Nb, Ti, Mo or V. In some embodiments the second reactant preferablycomprises tungsten.

In some embodiments the second reactant comprises a noble metal. Thenoble metal can be selected from the group: Au, Pt, Ir, Pd, Os, Ag, Rh,and Ru.

In some embodiments the second reactant comprises a metal halide (F, Cl,Br, I). In some preferred embodiments the second reactant comprises atransition metal halide. In some embodiments the second reactantpreferably comprises fluorine. In some embodiments, the second reactantcomprises WF₆, TaF₅, NbF₅, TiF₄, MoF_(x), VF_(x). In some embodimentsthe second reactant comprises WF₆.

The second reactant can be used to form a variety of different materialson the substrate. In some embodiments the second reactant reacts withthe first reactant on the substrate to form a metallic material on thesubstrate. Any of the metals disclosed above for the second reactant canbe in the film deposited on the substrate.

In some embodiments an elemental metal film can be formed, for example aW film. In some embodiments a metal nitride film can be formed. In someembodiments a metal silicide film can be formed.

In some embodiments a metallic or elemental metal film is first formedthrough reaction of the Si or B on the substrate surface and the secondreactant and later converted to a corresponding metal silicide or metalnitride through further processing. For example, the first metallic orelemental metal film may be exposed to a third reactant to convert it toa metal silicide or metal nitride.

In some embodiments further processing of the metallic material can bedone to dope the metallic material or convert the metallic material to ametal nitride or metal silicide. In some embodiments, for example, thematerial can be converted to a corresponding metal nitride using plasmaor a NH₃-treatment. In some embodiments an electrically conductivemetallic material can be converted to a more electrically resistivematerial or to a dielectric material by using different treatments anddepending on the starting metallic material.

In some embodiments multiple pulses of one of the reactants can beprovided prior to providing the next reactant. In some embodiments, anyexcess reactants can be removed prior to the provision of the nextreactant. In some embodiments the process chamber can be purged prior toprovision of the next reactant.

In some embodiments vapor phase precursors can be provided to thereaction space with the aid of an inert carrier gas. Removing excessreactants can include evacuating some of the contents of the reactionspace or purging the reaction space with helium, nitrogen or any otherinert gas. In some embodiments purging can comprise turning off the flowof the reactive gas while continuing to flow an inert carrier gas to thereaction space.

Deposition Temperature

In some embodiments the temperature is selected to facilitate theselective deposition. Deposition is generally defined as selective ifthe amount of the deposited material per surface area or volume (e.g.at/cm² or at/cm³) on the first surface is greater than the amount of thedeposited material per surface area or volume on the second surface. Theamount of material deposited on the surfaces can be determined bymeasuring the thicknesses of each layer. In some cases, the thicknessmeasurement might not be possible due to non-continuous film. In somecases the selectivity can be determined by measuring the deposited atomsper surface area or volume. As mentioned above, the selectivity can beexpressed as the ratio of material formed on the first surface to amountof material formed on the first and second surfaces combined.Preferably, the selectivity is above about 70%, above about 80%, morepreferably above 90%, even more preferably above 95%, and mostpreferably about 100%. In some cases selectivity above 80% may beacceptable for certain applications. In some cases selectivity above 50%may be acceptable for certain applications.

In some embodiments the deposition temperature is selected such that theselectivity is above about 90%. In some embodiments, the depositiontemperature is selected such that a selectivity of about 100% isachieved.

In some embodiments, the deposition temperature is selected such thatthe first precursor comprising silicon or boron forms a layer containingsilicon or boron on the first metal surface. In some embodiments thefirst precursor does not form a layer on the second surface comprisingsilicon, or forms a less than a complete layer on the second surface.

The particular temperature utilized can depend, in part, on the siliconor boron precursor that is selected along with the first surface ormetal and the second surface or dielectric on the substrate. Preferably,the silicon or boron source forms on the first metal surface instead ofthe second surface comprising silicon to form a layer comprising siliconor boron. Preferably, the layer comprising silicon or boron is about amonolayer or less. In some cases, more than a monolayer of silicon orboron can be formed. In some embodiments a layer of silicon or boronwith a thickness of from about 0.05 nm to about 4 nm is formed on themetal surface of the substrate. In some embodiments preferably a layerof silicon or boron with a thickness of from about 0.1 nm to about 2 nmis formed on the metal surface of the substrate. In some embodiments theformation of silicon or boron on the metal surface is self-limiting. Insome embodiments the layer comprising silicon or boron is formed bydecomposition.

In some cases the silicon or boron layer can form on both the metal andsilicon containing surfaces at higher temperatures. In such situations,the use of lower temperatures is preferred because the silicon or boroncan form on the metal surface at a lower temperature than the surfacecomprising silicon. Thus, the temperature can be selected such that thesilicon precursor interacts preferentially with the first surface ormetal surface relative to the second surface or silicon containingsurface.

In some embodiments deposition temperatures are selected to achieve thedesired level of selectivity. For example, a temperature can be selectedsuch that absorption of the silicon or boron containing precursor to thelow-k material is limited to an amount necessary to achieve a desiredlevel of selectivity.

The deposition temperature can be selected based on the silicon or boronsource and the particular substrate surfaces that are used (e.g. siliconcontaining surface and copper surface).

In some embodiments the deposition temperature is preferably less than200° C., more preferably less than about 175° C., more preferably lessthan about 150° C., most preferably less than about 110° C. In somecases temperatures of less than about 100° C. can be used. In someembodiments the deposition temperature range for selective depositionhaving selectivity of over 50% in films having thicknesses of less thanabout 5 nm (e.g. deposited W thickness) deposited using disilane and WF₆is from about 30° C. to about 200° C. In some embodiments desirablelevels of uniformity and selectivity can be achieved using depositiontemperature ranges from about 30° C. to about 110° C. In someembodiments desirable levels of uniformity and selectivity can beachieved using deposition temperature ranges from about 40° C. to about110° C. In some embodiments desirable levels of uniformity andselectivity can be achieved using deposition temperatures ranges lessthan about 100° C. In these temperature ranges a person skilled in theart can optimize the process to achieve desired or acceptable uniformityand selectivity for the films deposited using a particular reactor withparticular precursors.

In some embodiments the silicon or boron-containing precursor and thesecond metal precursor are provided at the same temperature and in thesame reaction space. In some embodiments the silicon precursor isprovided at a first deposition temperature and the second metal reactantis provided at a second deposition temperature. In practice, this maymean providing the first reactant in a first reaction space andproviding the second metal reactant in a second reaction space.

In some embodiments using disilane and depositing tungsten using WF₆ ona copper or cobalt surface, a selectivity of more than about 80%,preferably more than about 90%, relative to a surface comprising siliconcan be achieved with a deposition temperature of from about 30° C. toabout 110° C. The deposition temperature for trisilane can be even lowerthan the deposition temperature for disilane. In the above mentionedembodiments the deposited film may be, for example and withoutlimitation, a tungsten film.

In some embodiments the thickness of the film that is selectivelydeposited is less than about 10 nm, less than about 5 nm, about 4 nm orless or, in some embodiments, from about 1 nm to about 4 nm. However, insome cases a desired level of selectivity, for example more than 50%,more preferably more than 80%, is achieved with the thicknesses of theselectively deposited film being over about 10 nm.

In some embodiments a W film having a thickness of about 10 nm or lessis deposited selectively over Cu of Co on a substrate surface with aselectivity of greater than 50% relative to a silicon containingmaterial.

In some embodiments a W film having a thickness of about 5 nm or less isdeposited selectively over Cu or Co on a substrate surface with aselectivity of greater than about 80% relative to a silicon containingmaterial.

In some embodiments a W film having a thickness of about 3 nm or less isdeposited selectively over Cu or Co on a substrate surface with aselectivity of greater than about 90% relative to a silicon containingmaterial.

If a lower selectivity is preferred the temperature can be slightlyhigher than the temperature for processes that achieve more than 90%selectivity.

In some embodiments, deposition conditions and/or reactants are selectedsuch that etching of the silicon containing surfaces is avoided orminimized. For example, at higher temperatures metal fluorides can startfluorinating any Si—OH groups that may be present on the second surfaceand in some cases they can etch the silicon containing surface. Thus insome embodiments the deposition temperature is selected so that etchingof silicon containing surface is avoided or eliminated.

The substrate temperature during the provision of the second reactantcan be the same as the temperature during the provision of the siliconor boron containing reactant. In other embodiments, differenttemperatures may be used.

In embodiments where WF₆ is used as the second reactant with disilane asthe first reactant a temperature of from about 30° C. to about 110° C.can be used.

In some embodiments, the temperature of the substrate can be increasedwhen providing the second reactant to increase the conversion of themetal reactant. For example, a higher temperature can be used when TaF₅and NbF₅ are used as the second reactant. For example, when using TaF₅the temperatures can be over about 300° C. When using NbF₅ thetemperature can be above about 250° C. This can be accomplished byheating the substrate, using a higher reaction temperature for thesecond material or other means known to the skilled artisan.

Exemplary Process Flows

FIG. 3 is a flow chart generally illustrating a process 30 forselectively depositing a metal film on a first metallic surface of asubstrate relative to a second silicon containing surface according tocertain embodiments. The reaction chamber or chambers in which aselective deposition process will be performed are first subjected to anoptional reactor passivation process at step 31 to deposit a SiNpassivation layer on any chamber surfaces which connect directly withthe location of a subsequent selective deposition process. A substratecomprising a first metallic surface, such as a Co surface and secondsurface comprising silicon, such as a SiO₂ surface is provided and isoptionally outgassed. In some embodiments the substrate may be subjectedto an optional silicon-containing surface treatment at step 32, forexample to passivate the SiO₂ surface. The substrate may then besubjected to an optional first surface treatment process at step 33. Asdescribed above, in some embodiments the first surface treatment processmay comprise exposing the substrate to a plasma, for example a plasmagenerated from NH₃, H₂, or a combination of the two.

In some embodiments the plasma treatment process 33 may reduce the firstCo surface. In some embodiments the plasma treatment process may removea native oxide layer present on the first Co surface. In someembodiments the plasma treatment process may remove a passivation orhydrocarbon layer, for example a BTA layer, that may be present on thefirst Co surface.

In some embodiments steps 32 and 33 may be carried out in a differentreaction chamber or chambers from the reaction chamber being passivatedat step 31. That is, steps 32 and 33 may be carried out in a differentreaction chamber or chambers than the reaction chamber in which asubsequent selective deposition process is to be carried out in.Further, in some embodiments the reaction chamber passivation step 31may proceed concurrently with one or more of steps 32 and 33.

In some embodiments the substrate surface is optionally further annealedin an inert atmosphere after optional step 33. The annealing is carriedout at a temperature that is higher than the temperature during steps32, 33, or the following selective deposition steps 35-37. Thetemperature for the annealing process is preferably from about 150° C.to about 400° C., from about 150° C. to about 300° C., or from about200° C. to about 275° C. and in some cases at about 250° C. In someembodiments the substrate surface may optionally be further annealed ina NH₃ environment in order to create NH_(x)-surface terminations on anycobalt oxide present on the first Co surface.

Next, at step 34, the substrate is transferred into the chamber whichwas optionally passivated at step 31 and a silicon or boron source isprovided to the substrate, such that a silicon or boron containingspecies is deposited on the Co surface at step 35. In some embodimentsthe silicon source is disilane. In some embodiments, the disilane can beselectively decomposed on the Co surface relative to the SiO₂ surfaceusing a deposition temperature at which the silicon precursor formssilicon on the Co surface but does form silicon on the SiO₂ surface. Forexample the deposition may be from about 30° C. to about 110° C. In someembodiments, the silicon or boron source reacts with the Co surface in aself-limiting manner. It is believed that the Co surface can facilitatethe formation of silicon relative to the formation on the SiO₂ surface.

In some embodiments a layer comprising silicon or boron with a thicknessof from about 0.05 nm to about 4 nm is formed on the Co surface of thesubstrate in each deposition cycle. In some embodiments a layercomprising silicon or boron with a thickness of from about 0.1 nm toabout 2 nm is formed on the Co surface of the substrate in each cycle.In preferred embodiments the formation of a layer comprising silicon orboron on the metal surface is self-limiting. Thus, at most a monolayercomprising silicon or boron is formed in each cycle.

After the silicon or boron containing layer is formed on the Co layer asecond reactant, such as a metal halide, for example WF₆, is used toconvert the layer comprising silicon or boron to a layer comprising thecorresponding metal from the second reactant, such as tungsten, at step36. In some embodiments, WF₆, TaF₅, NbF₅ or other compounds that areable to react with the Si or B layer are introduced to the substratesurface to form a metallic layer or metal silicide. In some embodiments,the silicon or boron precursor (e.g. disilane) and second reactant (suchas metal halide) pulses can be repeated at step 37 until a metalliclayer with a desired thickness is formed. In some embodiments themetallic layer is an elemental metal, for example W. In someembodiments, the metallic layer can include additional elements, such asSi, B, N, and other dopants. In some embodiments the metallic layer isfurther treated to form a different material. For example an elementalmetal layer can be treated using a third reactant to form a metalnitride or metal silicide.

A deposition cycle can be defined as providing the silicon or boronprecursor and providing the second metal reactant, that is, steps 35 and36. In some embodiments no other reactants are provided in thedeposition cycle. In some embodiments the deposition cycle is repeatedto form a W layer with a desired thickness. In some embodiments a Wlayer with a thickness from about 0.05 nm to about 4 nm is formed ineach cycle. In some embodiments, preferably a W layer with a thicknessfrom about 0.1 nm to about 2 nm is formed in each cycle. In someembodiments the W layer has a thickness of about 1-2 nm. In otherembodiments the thickness of the deposited W layer is above about 2 nm,in some cases above about 30 nm, and in some cases above about 50 nm. Inpreferred embodiments the layer has thickness of less than 10 nm.

In some embodiments the deposition cycle is repeated 10 or more times.In some embodiments, the deposition cycle is repeated at least 50 times.In some embodiments the deposition cycle is repeated about 100 times ormore. The number of cycles can be selected based on the desiredthickness of the W layer.

In some embodiments, no other reactants are provided besides theprecursor comprising silicon or boron and the second metal reactant.

In some embodiments the material comprising the first surface, such ascobalt, is not converted or reacted to form another compound during theselective deposition cycle.

In some embodiments, after the one or more deposition cycles arecompleted a half deposition cycle can be performed at step 38. Forexample, a silicon or boron precursor pulse or alternatively a secondmetal reactant can be provided. In some embodiments, after the one ormore deposition cycles a silicon or boron precursor pulse is provided.When a silicon or boron precursor pulse (or other metal reactant) isprovided, the formed material can form a sacrificial layer of siliconoxide or boron oxide (or a metal oxide) when exposed to air or an oxygencontaining atmosphere. The sacrificial layer can prevent the metallicmaterial underneath the silicon oxide or boron oxide layer fromoxidizing when exposed to air or an oxygen-containing atmosphere outsidethe reactor. The formed silicon oxide or boron oxide layer can beremoved in further processing steps, for example with a single pulse ofmetal source chemicals described herein, preferably with WF₆, TaF₅,NbF₅, TiF₄, MoF_(x) or VF_(x) and more preferably with WF₆.

In some embodiments the entire process flow is carried out in a singlereaction chamber; for example in a single process module. However, inother embodiments the various steps are carried out in two or morereaction chambers. For example, in some embodiments the first surfacetreatment and silicon containing surface treatment processes (if used)are carried out in a first reaction chamber while the selectivedeposition may be carried out in a second, different reaction chamber.In some embodiments the second, different reaction chamber may also betreated to form a passivation layer therein. If the optional heat annealstep is needed or desired, the substrate may then be transported to asecond reaction chamber where the heat anneal (if used) and selectivedeposition are carried out. In some embodiments the anneal step iscarried out in a second reaction chamber, and the substrate istransported back to the first reaction chamber, or to a third reactionchamber where selective deposition is carried out. In some embodimentsthe first surface treatment and silicon containing surface treatment (ifused) are carried out in first reaction chamber and the selectivedeposition is carried out in a second, different reaction chamberwithout the heat anneal step in between the first surface treatment anddepositions step. The substrate may be cooled down for a period of timeprior to transport, if required. In some embodiments, the cool down iscarried out for about 0 to 30 min, or about 0 to 10 minutes, at apressure ranging from vacuum to about 2 atm, or about 0.1 torr to about760 torr, or about 1 torr to about 760 torr. The substrate may betransported, for example, under vacuum or in the presence of N₂ (andpossibly some O₂) at about 1 to 1000 torr.

FIG. 4 is a flow chart generally illustrating a process 40 forselectively depositing a metal film on a first metallic surface of asubstrate relative to a second silicon containing surface according tocertain other embodiments. The reaction chamber or chambers in which aselective deposition process will be performed are first subjected to anoptional reactor passivation process at step 41. A substrate comprisinga first metallic surface, preferably a Cu surface and second surfacecomprising silicon, such as a SiO₂ surface is provided and is optionallyoutgassed. In some embodiments the substrate may be subjected to anoptional silicon-containing surface treatment at step 42, for example topassivate the SiO₂ surface. The substrate may then be subjected to anoptional first surface treatment process at step 43. As described above,in some embodiments the surface first surface treatment process maycomprise exposing the substrate to one or more first surface treatmentreactants.

In some embodiments the treatment process 43 may reduce the firstmetallic surface. In some embodiments the treatment process may remove anative oxide layer present on the first metallic surface. In someembodiments the treatment process may remove a passivation orhydrocarbon layer that may be present on the first metallic surface, forexample the treatment process may remove a BTA layer present on the Cusurface. In some embodiments a passivation layer, for example a BTAlayer on the Cu surface may have been deposited to protect the Cusurface from oxidation during other processing steps, for examplechemical-mechanical planarization. However, such a passivation layermust be removed prior to the selective deposition process.

In some embodiments the treatment process comprises exposing thesubstrate to a treatment reactant. In some embodiments the treatmentreactant is a vapor phase organic reactant. In some embodimentstreatment reactant may contain at least one alcohol group and may bepreferably selected from the group consisting of primary alcohols,secondary alcohols, tertiary alcohols, polyhydroxy alcohols, cyclicalcohols, aromatic alcohols, and other derivatives of alcohols. In someembodiments the treatment reactant may comprise formic acid or HCl.

Temperature during the treatment process 43 may be, for example, fromabout room temperature to about 400° C., from about 100° C. to about400° C., from about 100° C. to about 130° C., or form about 30° C. toabout 110° C.

In some embodiments steps 42 and 43 may be carried out in a differentreaction chamber or chambers from the reaction chamber being passivatedat step 41. That is, steps 42 and 43 may be carried out in a differentreaction chamber or chambers than the reaction chamber in which asubsequent selective deposition process is to be carried out in.Further, in some embodiments the reaction chamber passivation step 41may proceed concurrently with one or more of steps 42 and 43.

In some embodiments the substrate surface is optionally further annealedin an inert atmosphere after optional step 43. The annealing is carriedout at a temperature that is higher than the temperature during steps42, 43, or the following selective deposition steps 45-47. Thetemperature for the annealing process is preferably from about 150° C.to about 400° C., from about 150° C. to about 300° C., or from about200° C. to about 275° C. and in some cases at about 250° C. In someembodiments the substrate surface may optionally be further annealed ina NH₃ environment in order to create NH_(x)— surface terminations on anmetal oxide present on the Cu surface.

Next, at step 44, the substrate is transferred into the chamber whichwas optionally passivated at step 41 and a silicon or boron source isprovided to the substrate, such that a silicon or boron containingspecies is deposited on the Cu surface at step 45. In some embodimentsthe silicon source is disilane. In some embodiments, the disilane can beselectively decomposed on the Cu surface relative to the siliconcontaining surface using a temperature at which the silicon precursorforms silicon on the Cu surface but does form silicon on the SiO₂surface. In some embodiments, the silicon or boron source reacts withthe Cu surface in a self-limiting manner. It is believed that the Cusurface can facilitate the formation of silicon relative to theformation on the SiO₂ surface.

In some embodiments a layer comprising silicon or boron with a thicknessof from about 0.05 nm to about 4 nm is formed on the Cu surface of thesubstrate in each deposition cycle. In some embodiments a layercomprising silicon or boron with a thickness of from about 0.1 nm toabout 2 nm is formed on the Cu surface of the substrate in each cycle.In preferred embodiments the formation of a layer comprising silicon orboron on the Cu surface is self-limiting. Thus, at most a monolayercomprising silicon or boron is formed in each cycle.

After the silicon or boron containing layer is formed on the Cu surfacea second reactant, such as a metal halide, is used to convert the layercomprising silicon or boron to a layer comprising the correspondingmetal from the second reactant, such as the metal in the metal halide,at step 46. In some embodiments, WF₆, TaF₅, NbF₅ or other compounds thatare able to react with the Si or B layer are introduced to the substratesurface to form a metallic layer or metal silicide. In some embodiments,the silicon or boron precursor (e.g. disilane) and second reactant (suchas metal halide) pulses can be repeated at step 47 until a metalliclayer with a desired thickness is formed. In some embodiments themetallic layer is an elemental metal, for example W. In someembodiments, the metallic layer can include additional elements, such asSi, B, N, and other dopants. In some embodiments the metallic layer isfurther treated to form a different material. For example an elementalmetal layer can be treated using a third reactant to form a metalnitride or metal silicide.

A deposition cycle can be defined as providing the silicon or boronprecursor and providing the second metal reactant, that is, steps 45 and46. In some embodiments no other reactants are provided in thedeposition cycle. In some embodiments the deposition cycle is repeatedto form a metallic layer with a desired thickness. In some embodiments ametallic layer with a thickness from about 0.05 nm to about 4 nm isformed in each cycle. In some embodiments, preferably a metallic layerwith a thickness from about 0.1 nm to about 2 nm is formed in eachcycle. In some embodiments the metallic layer has a thickness of about1-2 nm. In other embodiments the thickness of the deposited metalliclayer is above about 2 nm, in some cases above about 30 nm, and in somecases above about 50 nm. In preferred embodiments the layer hasthickness of less than 10 nm.

In some embodiments the deposition cycle is repeated 10 or more times.In some embodiments, the deposition cycle is repeated at least 50 times.In some embodiments the deposition cycle is repeated about 100 times ormore. The number of cycles can be selected based on the desiredthickness of the metallic layer.

In some embodiments, no other reactants are provided besides theprecursor comprising silicon or boron and the second metal reactant.

In some embodiments the material comprising the first surface, such ascopper, is not converted or reacted to form another compound during theselective deposition cycle.

In some embodiments, after the one or more deposition cycles arecompleted a half deposition cycle can be performed at step 48. Forexample, a silicon or boron precursor pulse or alternatively a secondmetal reactant can be provided. In some embodiments, after the one ormore deposition cycles a silicon or boron precursor pulse is provided.When a silicon or boron precursor pulse (or other metal reactant) isprovided, the formed material can form a sacrificial layer of siliconoxide or boron oxide (or a metal oxide) when exposed to air or an oxygencontaining atmosphere. The sacrificial layer can prevent the metallicmaterial underneath the silicon oxide or boron oxide layer fromoxidizing when exposed to air or an oxygen-containing atmosphere outsidethe reactor. The formed silicon oxide or boron oxide layer can beremoved in further processing steps, for example with a single pulse ofmetal source chemicals described herein, preferably with WF₆, TaF₅,NbF₅, TiF₄, MoF_(x) or VF_(x) and more preferably with WF₆.

In some embodiments the entire process flow is carried out in a singlereaction chamber; for example in a single process module. However, inother embodiments the various steps are carried out in two or morereaction chambers. For example, in some embodiments the first surfacetreatment and silicon containing surface treatment processes (if used)are carried out in a first reaction chamber while the selectivedeposition may be carried out in a second, different reaction chamber.In some embodiments the second, different reaction chamber may also betreated to form a passivation layer therein. If the optional heat annealstep is needed or desired, the substrate may then be transported to asecond reaction chamber where the heat anneal (if used) and selectivedeposition are carried out. In some embodiments the anneal step iscarried out in a second reaction chamber, and the substrate istransported back to the first reaction chamber, or to a third reactionchamber where selective deposition is carried out. In some embodimentsthe first surface treatment and silicon containing surface treatment (ifused) are carried out in first reaction chamber and the selectivedeposition is carried out in a second, different reaction chamberwithout the heat anneal step in between the first surface treatment anddepositions step. The substrate may be cooled down for a period of timeprior to transport, if required. In some embodiments, the cool down iscarried out for about 0 to 30 min, or about 0 to 10 minutes, at apressure ranging from vacuum to about 2 atm, or about 0.1 torr to about760 torr, or about 1 torr to about 760 torr. The substrate may betransported, for example, under vacuum or in the presence of N₂ (andpossibly some O₂) at about 1 to 1000 torr.

FIG. 5 is a flow chart generally showing an exemplary reaction chamberpassivation process 50 in accordance with some embodiments. In someembodiments the reaction chamber passivation process may enableselective deposition, improve selectivity, and/or increase the number ofcycles before selectivity is lost during a selective deposition process.

A reaction chamber in which a selective deposition process, for examplea W selective deposition process, is to be performed is provided at step51. The reaction chamber is provided with no wafers or substrateswithin. In some embodiments a selective deposition process may have beencarried out on a wafer or wafers within the reaction chamber, which isthen removed at step 51 so that there is no wafer within the reactionchamber. In some embodiments a wafer or wafers which will be subjectedto a selective deposition process in the reaction chamber may besubjected to other processing before, during, or after the reactionchamber passivation process. For example a wafer may be subjected to asurface first surface treatment process in a second, different reactionchamber during the reaction chamber passivation process.

In some embodiments a passivation layer is deposited or formed at step52 on the interior surfaces of the reaction chamber and any otherlocations which may be exposed to a precursor or reactant during aselective deposition process. In some embodiments the passivation layeris deposited or formed on the interior surface of the reaction chamber,the chamber showerhead, and/or any other parts of the chamber which mayconnect to the space where a selective deposition process will occur. Insome embodiments the passivation layer may be deposited on any surfacein the reaction chamber that is not a substrate.

In some embodiments the passivation layer, for example a layer of SiN,may be formed by a vapor deposition process, for example a PEALDprocess. In some embodiments the SiN layer may be formed by a processcomprising one or more passivation layer deposition cycles comprisingalternately and sequentially exposing the reaction chamber to a firstsilicon precursor and second nitrogen precursor. The passivation layerdeposition cycle may optionally be repeated until a SiN passivationlayer of a desired thickness has been formed.

In some embodiments the silicon precursor used in the passivation layerdeposition process may comprise a silane, for example disilane. In someembodiments the nitrogen precursor may atomic nitrogen, nitrogenradicals, nitrogen plasma, or combinations thereof. In some embodimentsthe nitrogen precursor may further comprise atomic hydrogen, hydrogenradicals, hydrogen plasma, or combinations thereof. In some embodimentsthe nitrogen precursor may comprise plasma generated from N₂. In someembodiments the nitrogen precursor may comprise a plasma generated fromN₂ and H₂ In some embodiments the nitrogen precursor may comprise plasmagenerated from N₂ and a noble gas, for example argon. In someembodiments the nitrogen precursor may comprise plasma generated fromN₂, H₂, and a noble gas, for example argon.

In some embodiments, subsequent to formation of the passivation layer atstep 52, a wafer or wafers are transferred into the reaction chamber atstep 53. A selective deposition process, for example a W selectivedeposition process and any other desired processes may then be performedat step 54. In some embodiments, subsequent to the selective depositionprocess any wafer or wafers present in the reaction chamber may then betransferred out of the reaction chamber at step 55. In some embodimentsthe reaction chamber passivation process may optionally be repeated atstep 56. In some embodiments a wafer or wafers may be transferred intothe reaction chamber and another selective deposition process may becarried out again prior to optionally repeating the reaction chamberpassivation process. That is, in some embodiments the reaction chamberpassivation process may be repeated after every 1, 5, 10, 20, 50, ormore wafers have been subjected to a selective deposition process. Insome embodiments the reaction chamber passivation process may berepeated after a certain number of cycles of a selective depositionprocess have been performed. In some embodiments the reaction chamberpassivation process may be repeated after every 50, 100, 150, or moreselective deposition cycles.

EXAMPLES

Sample substrates having a first metallic surface comprising Cu and asecond dielectric surface comprising a low-k dielectric material havinga dielectric constant of 3.0 were provided and the first Cu surface waspassivated by depositing an organic layer thereon, having a thickness ofabout 1 nm to 2 nm. A native copper oxide layer was also present betweenthe Cu surface and the organic layer, having a thickness of about 1 nm.Substrates comprising only a Co surface, along with a native cobaltoxide surface layer, were also provided to act as controls.

The sample substrates comprising a first Cu surface and a seconddielectric surface, along with the control substrates comprising a Cosurface were subjected to various first surface treatment processes inorder to investigate the effects of such processes on a subsequentlyperformed selective deposition process for depositing W on the firstsurface of the sample substrate relative to the second surface, asdescribed herein and according to some embodiments. The various firstsurface treatment processes comprised exposing the substrates to aplasma generated from various gases. Each plasma was generated via RFpower of about 200 W at a pressure of about 350 Pa, while the substratewere exposed for about 10 seconds. The substrate temperature during eachof the first surface treatment processes was about 150° C.

The first sample and control substrates were subjected to a firstsurface treatment process comprising exposing the substrate to a plasmagenerated from a gas comprising H₂ at a flow rate of 1000 sccm, with anoble gas acting as a carrier gas. The sample and control substrateswere then subjected to a selective deposition process for selectivelydepositing W on the first Cu and Co surfaces relative to the seconddielectric surface. The control substrate comprising a Co surface wasincluded in order to investigate the capability of the first surfacetreatment process to effectively reduce and/or remove the native oxidelayer present thereon.

As shown in FIG. 6A, W was deposited on both the first Cu surface andthe second dielectric surface. W deposition was also observed on thesubstrate comprising a Co surface, indicating that the native oxidesurface layer had been effectively reduced and/or removed. Accordingly,the above-described first surface treatment process did not enhance theselectivity of the selective deposition process, and instead reduced theselectivity of the process. Without being bound by any one theory, it isbelieved that exposure to the plasma generated from H₂ under theabove-described conditions damaged the second dielectric surface,creating surface sites which enabled W deposition thereon.

The second sample and control substrates were subjected to a firstsurface treatment process comprising exposing the substrate to a plasmagenerated from a gas comprising H₂ and N₂ at a flow rate of 1000 sccm,with a noble gas acting as a carrier gas. The sample and controlsubstrates were then subjected to a selective deposition process forselectively depositing W on the first Cu and Co surfaces relative to thesecond dielectric surface. The control substrate comprising a Co surfacewas included in order to investigate the capability of the first surfacetreatment process to effectively reduce and/or remove the native oxidelayer present thereon.

As shown in FIG. 6B, W was deposited on both the first Cu surface andthe second dielectric surface. W deposition was also observed on thesubstrate comprising a Co surface, indicating that the native oxidesurface layer had been effectively reduced and/or removed. Accordingly,the above-described first surface treatment process did not enhance theselectivity of the selective deposition process, and instead reduced theselectivity of the process. Without being bound by any one theory, it isbelieved that exposure to the plasma generated from H₂ and N₂ under theabove-described conditions damaged the second dielectric surface,creating surface sites which enabled W deposition thereon.

The third sample and control substrates were subjected to a firstsurface treatment process comprising exposing the substrate to a plasmagenerated from a gas comprising NH₃ at a flow rate of 1000 sccm, with anoble gas acting as a carrier gas. The sample and control substrateswere then subjected to a selective deposition process for selectivelydepositing W on the first Cu and Co surfaces relative to the seconddielectric surface. The control substrate comprising a Co surface wasincluded in order to investigate the capability of the first surfacetreatment process to effectively reduce and/or remove the native oxidelayer present thereon.

As shown in FIG. 6C, W was deposited on both the first Cu surface andthe second dielectric surface. No W deposition was observed on thesubstrate comprising a Co surface, indicating that the native oxidesurface layer had not been effectively reduced and/or removed.Accordingly, the above-described first surface treatment process did notenhance the selectivity of the selective deposition process, and insteadreduced the selectivity of the process. Without being bound by any onetheory, it is believed that exposure to the plasma generated from NH₃under the above-described conditions damaged the second dielectricsurface, creating surface sites which enabled W deposition thereon.

The fourth sample and control substrates were subjected to a firstsurface treatment process comprising exposing the substrate to a plasmagenerated from a gas comprising H₂ and NH₃ at a flow rate of 1000 sccm,with a noble gas acting as a carrier gas. The sample and controlsubstrates were then subjected to a selective deposition process forselectively depositing W on the first Cu and Co surfaces relative to thesecond dielectric surface. The control substrate comprising a Co surfacewas included in order to investigate the capability of the first surfacetreatment process to effectively reduce and/or remove the native oxidelayer present thereon.

As shown in FIG. 6D, W was deposited on both the first Cu surface andparticulate W material was deposited on the second dielectric surface.No W deposition was observed on the substrate comprising a Co surface,indicating that the native oxide surface layer had not been effectivelyreduced and/or removed. Accordingly, the above-described first surfacetreatment process did not enhance the selectivity of the selectivedeposition process, and instead reduced the selectivity of the process.Without being bound by any one theory, it is believed that exposure tothe plasma generated from H₂ and NH₃ under the above-describedconditions damaged the second dielectric surface, creating surface siteswhich enabled W deposition thereon.

The fifth sample and control substrates were subjected to a firstsurface treatment process comprising exposing the substrate to a plasmagenerated from a gas comprising HCOOH, NH₃, and H₂ at a flow rate of1000 sccm, with a noble gas acting as a carrier gas. The ratio of HCOOHto NH₃ to H₂ was 1:1:19. The sample and control substrates were thensubjected to a selective deposition process for selectively depositing Won the first Cu and Co surfaces relative to the second dielectricsurface. The control substrate comprising a Co surface was included inorder to investigate the capability of the first surface treatmentprocess to effectively reduce and/or remove the native oxide layerpresent thereon.

As shown in FIG. 7, W was selectively deposited on the first Cu surfaceand no W deposition was observed on the second dielectric surface,indicating that the first surface treatment enhanced or enabledselective W deposition. W deposition was also observed on the substratecomprising a Co surface, indicating that the native oxide surface layerhad been effectively reduced and/or removed. Without being bound by anyone theory, it is believed that exposure to the plasma generated fromHCOOH, NH₃, and H₂ under the above-described conditions did notsignificantly damage the second dielectric surface, while removing theorganic surface layer and reducing and/or removing the native oxide fromthe first metallic surface in order to enhanced selective W depositionthereon.

A summary of the results of the above-described first surface treatmentprocesses and the effects on selective W deposition are provided inTable 1, below. The first surface treatment process comprisingcontacting the substrate with a plasma generated from a gas comprisingHCOOH, NH₃, and H₂ was the only process investigated which was able toachieved deposition on the Cu and Co surfaces while maintainingselectivity relative to the dielectric surface. Accordingly, this firstsurface treatment process was able to remove and organic surface layerand reduce and/or remove a native oxide layer from the Cu surface, andreduce and/or remove a native oxide layer from the Co surface, while notsignificantly damaging the second dielectric surface so as to maintainor enhance the selectivity of the selective W deposition process.

TABLE 1 Summary of results for various first surface treatment processesand effects on selective deposition processes for depositing W onmetallic surfaces relative to a dielectric surface. First Surface WDeposition W Deposition W Deposition Treatment Plasma on Cu on Low-k onCo Generation Gas Surface Surface Surface H₂ ∘ ∘ ∘ H₂/N₂ ∘ ∘ ∘ NH₃ ∘ ∘ xNH₃/H₂ ∘ ∘ (W particles) x HCOOH/NH₃/H₂ ∘ x ∘

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than or equal to 10% of, within less than or equal to 5% of, withinless than or equal to 1% of, within less than or equal to 0.1% of, andwithin less than or equal to 0.01% of the stated amount. If the statedamount is 0 (e.g., none, having no), the above recited ranges can bespecific ranges, and not within a particular % of the value. Forexample, within less than or equal to 10 wt./vol. % of, within less thanor equal to 5 wt./vol. % of, within less than or equal to 1 wt./vol. %of, within less than or equal to 0.1 wt./vol. % of, and within less thanor equal to 0.01 wt./vol. % of the stated amount.

The terms “film” and “thin film” are used herein for simplicity. “Film”and “thin film” are meant to mean any continuous or non-continuousstructures and material deposited by the methods disclosed herein. Forexample, “film” and “thin film” could include 2D materials, nanorods,nanotubes or nanoparticles or even single partial or full molecularlayers or partial or full atomic layers or clusters of atoms and/ormolecules. “Film” and “thin film” may comprise material or layer withpinholes, but still be at least partially continuous.

Although certain embodiments and examples have been discussed, it willbe understood by those skilled in the art that the scope of the claimsextend beyond the specifically disclosed embodiments to otheralternative embodiments and/or uses and obvious modifications andequivalents thereof.

What is claimed is:
 1. A process for selectively depositing a film on afirst metallic surface of a substrate relative to a second dielectricsurface of the same substrate, the process comprising: performing afirst metallic surface treatment process comprising removing a surfacelayer from the first metallic surface of the substrate such that asignificant amount of new surface groups or ligands are not provided onthe second dielectric surface by the first metallic surface treatmentprocess, wherein the first metallic surface treatment process comprisesexposing at least the first metallic surface of the substrate to aplasma generated from a gas comprising HCOOH; and selectively depositinga film on the treated first metallic surface of the substrate relativeto the second dielectric surface of the substrate with a selectivity ofgreater than about 50%.
 2. The process of claim 1, wherein the firstmetallic surface treatment process comprises exposing the first metallicsurface of the substrate and the second dielectric surface of thesubstrate to the plasma generated from the gas.
 3. The process of claim1, wherein the first metallic surface treatment process furthercomprises reducing and/or removing a metal oxide layer present on thefirst metallic surface of the substrate.
 4. The process of claim 1,wherein the removed surface layer comprises an organic material.
 5. Theprocess of claim 4, wherein the removed surface layer comprises apassivation layer.
 6. The process of claim 5, wherein the removedsurface layer comprises benzotriazole (BTA).
 7. The process of claim 1,wherein the gas comprises formic acid (HCOOH) and H₂.
 8. The process ofclaim 1, wherein the gas comprises HCOOH, NH₃, and H₂.
 9. The process ofclaim 8, wherein the gas is provided by a carrier gas comprising a noblegas.
 10. The process of claim 1, wherein a temperature of the substrateduring the first metallic surface treatment process is about 300° C. 11.The process of claim 1, wherein the first metallic surface treatmentprocess comprises exposing at least the first metallic surface of thesubstrate to the plasma for from about 1 second to about 10 minutes. 12.The process of claim 1, wherein the plasma is generated by supplying RFpower of from about 10 W to about 3000 W to the gas.
 13. The process ofclaim 12, wherein the frequency of the RF power is from about 1 MHz toabout 10 GHz.
 14. The process of claim 1, wherein the pressure of thegas from which the plasma is generated is from about 1 Pa to about 5000Pa.
 15. The process of claim 1, wherein the selectively deposited filmcomprises tungsten.
 16. The process of claim 1, wherein the firstmetallic surface comprises copper or cobalt.
 17. The process of claim 1,wherein the second dielectric surface comprises silicon.
 18. A processfor selectively depositing a film on a first metallic surface of asubstrate relative to a second dielectric surface of the same substrate,the process comprising: performing a first metallic surface treatmentprocess comprising removing a surface layer from the first metallicsurface of the substrate by exposing at least the first metallic surfaceof the substrate to a plasma generated from a gas comprising HCOOH; andselectively depositing a film on the first metallic surface of thesubstrate relative to the second dielectric surface of the substratewith a selectivity of greater than about 50%.